📋 Descripción General: B2B Unpaid Invoices

When a business client fails to pay for goods or services you provided, California law gives you powerful tools to collect what you are owed. A well-crafted carta de demanda is often the first step to recovering payment without costly litigio.

Cuándo Usar Esta Guía

This guide is for business-to-business (B2B) invoice collection when:

💰 Invoice is Past Due

The payment deadline stated on your invoice has passed without payment

📩 No Response

The debtor has ignored your payment reminders or informal collection attempts

👥 B2B Transaction

Both you and the debtor are businesses (not consumer debt)

✅ Work Completed

You fully performed your obligations - goods delivered or services rendered

Common B2B Invoice Dispute Scenarios

💼 Servicios Rendered But Not Paid

▼

You provided professional services (consulting, marketing, IT, legal, accounting, etc.) and the client accepted the work but has not paid the invoice. This is the most common B2B collection scenario. Your demand should emphasize completion of the work and acceptance by the client.

📦 Goods Delivered But Not Paid

▼

You sold and delivered goods to a business customer who has not paid. California Commercial Code provisions apply to sales of goods. Document delivery confirmation, acceptance of goods, and any inspección period that has passed without rejection.

💲 Partial Payment Received

▼

The client made a partial payment but owes a remaining balance. Your demand should acknowledge the partial payment, state the exact remaining balance, and demand full payment of the outstanding amount plus any applicable late fees and interest.

🔁 Ongoing Relationship with Outstanding Balance

▼

You have an ongoing business relationship with multiple invoices, some of which remain unpaid. Your demand should itemize all outstanding invoices, indicate which are past due, and consider whether to continue providing services while collection is pending.

👍 Lo Que Puede Recuperar

  • Principal amount - The full invoice amount owed
  • Prejudgment interest - 10% per year on the unpaid amount (Cal. Civ. Code 3287)
  • Late fees - If specified in your contract or invoice terms
  • Abogado fees - If your contract includes an abogado fee provision (Cal. Civ. Code 1717)
  • Collection costs - If specified in your contract

⚠ Prescripción

California has strict time limits for filing unpaid invoice claims:

  • Written contracts: 4 año(s) desde the date payment was due (CCP 337)
  • Oral contracts: 2 año(s) desde the date payment was due (CCP 339)
  • Open book accounts: 4 año(s) desde the last item in the account (CCP 337)

Do not delay - act quickly to preserve sus derechos and maximize interest recuperación.

💰 Calcule Sus Daños

Under California law, puede recuperar the full invoice amount plus interest and other costs. Here is how to calculate your total reclamación.

Damage Type Descripción
Principal Amount The total unpaid invoice amount for goods delivered or services rendered.
Prejudgment Interest (10%) Under Cal. Civ. Code 3287(a), 10% per year calculated from the date each invoice was due until payment. Interest accrues daily.
Contractual Late Fees If your contract or invoice terms specify late fees (e.g., 1.5% per month), these are recoverable if they are a reasonable estimate of actual daños.
Honorarios de Abogado Under Cal. Civ. Code 1717, recoverable if your contract contains an abogado fee provision. The prevailing party gets fees.
Collection Costs If your contract provides for recuperación of collection costs, you can include documented collection expenses.

📊 Ejemplo de Cálculo de Daños

Example: Consulting Servicios Invoice - 18 Months Overdue

Original invoice amount $45,000.00
Prejudgment interest (10% x 1.5 years) $6,750.00
Contractual late fees (if applicable) $2,025.00
Estimated abogado fees (if contract provides) $5,000.00
TOTAL DEMANDA $58,775.00

Calculating Prejudgment Interest

The formula for calculating prejudgment interest is:

🔎 Interest Calculation Formula

Principal x 0.10 x (Days Past Due / 365) = Prejudgment Interest

Example: $50,000 invoice, 547 días overdue
$50,000 x 0.10 x (547 / 365) = $7,493.15 in interest

⚠ Late Fees vs. Prejudgment Interest

If your contract specifies late fees (e.g., 1.5% per month = 18% annually), you generally must choose between contractual late fees OR statutory prejudgment interest - you cannot recover both on the same amount. Calculate which is higher and demand that amount.

✅ Lista de Evidencias

Gather these documents before sending your carta de demanda. Strong documentation increases your leverage and supports litigio if needed.

📄 Documentos del Contrato

  • ✓ Signed service agreement, sales contract, or master agreement
  • ✓ Purchase orders or work orders
  • ✓ Statements of work or project scopes
  • ✓ Terms and conditions (if referenced in contract)

📋 Invoices

  • ✓ All unpaid invoices with dates and amounts
  • ✓ Invoice delivery confirmation (email receipts)
  • ✓ Payment terms stated on each invoice
  • ✓ Partial payment records (if applicable)

📦 Delivery Confirmations

  • ✓ Signed delivery receipts or bills of lading
  • ✓ Shipping tracking confirmations
  • ✓ Service completion sign-offs
  • ✓ Client approval emails or acceptance documentation

📩 Comunicaciones

  • ✓ Email correspondence about the project/order
  • ✓ Payment reminder emails sent
  • ✓ Any promises to pay or payment plans discussed
  • ✓ Any disputes or demandas raised (and your responses)

🔒 Documentation Best Practices

  • Keep all originals in a safe location
  • Create a chronological timeline of the business relationship
  • Save all emails in PDF format with headers showing delivery
  • Calculate a running total of principal + interest through the current date

📝 Texto Modelo

Copiar and customize these paragraphs for different unpaid invoice scenarios.

Servicios Rendered Scenario

Servicios Rendered - Opening
I am writing on behalf of [YOUR COMPANY] to formally demand payment for professional services rendered to [DEBTOR COMPANY]. Despite our satisfactory completion of all contracted work and your acceptance of nuestro servicios, Invoice No. [INVOICE NUMBER] dated [INVOICE DATE] in the amount of $[AMOUNT] remains unpaid. This invoice was due on [DUE DATE] and is now [NUMBER] days past due.

Goods Delivered Scenario

Goods Delivered - Opening
This letter constitutes a formal demand for payment on behalf of [YOUR COMPANY]. On [DELIVERY DATE], we delivered [DESCRIPTION OF GOODS] to [DEBTOR COMPANY] de conformidad con Purchase Order No. [PO NUMBER]. Your company accepted delivery of these goods, and the inspección period has passed without rejection. Invoice No. [INVOICE NUMBER] in the amount of $[AMOUNT] was due on [DUE DATE] and remains unpaid. Under California Commercial Code Section 2607, you are obligated to pay for goods accepted.

Partial Payment Scenario

Partial Payment - Opening
This letter demands immediate payment of the outstanding balance owed by [DEBTOR COMPANY] to [YOUR COMPANY]. While we acknowledge receipt of your partial payment of $[PARTIAL PAYMENT AMOUNT] on [PAYMENT DATE], a balance of $[REMAINING BALANCE] remains unpaid on Invoice No. [INVOICE NUMBER]. This remaining balance has been outstanding since [ORIGINAL DUE DATE]. We demand immediate payment of the full remaining balance plus accrued interest.

Ongoing Relationship Scenario

Ongoing Relationship - Opening
Despite our valued ongoing business relationship, [DEBTOR COMPANY] has allowed multiple invoices to become significantly past due. As of [CURRENT DATE], the following invoices from [YOUR COMPANY] remain unpaid: Invoice No. [INVOICE 1] dated [DATE] for $[AMOUNT]; Invoice No. [INVOICE 2] dated [DATE] for $[AMOUNT]. The total outstanding balance is $[TOTAL]. We must receive payment before we can continue providing services.

Base Legal Paragraph (Use for All Scenarios)

Base Legal - California Law
Under California código civil Section 3287(a), we tienen derecho a prejudgment interest at the rate of 10% per annum on the outstanding balance, calculated from the date each invoice became due. Adicionalmente, de conformidad con California código civil Section 1717 and the abogado fee provision in our agreement, we tienen derecho a recover reasonable abogado fees and costs incurred in collecting this debt. If litigio becomes necessary, we will seek the full amount owed plus all accrued interest, abogado fees, and tribunal costs.

Demand and Deadline Paragraph

Demand and Deadline
DEMANDA IS HEREBY MADE for payment of the total amount of $[TOTAL WITH INTEREST], consisting of $[PRINCIPAL] in principal and $[INTEREST] in accrued prejudgment interest through [DATE]. This amount must be received by [YOUR COMPANY] a más tardar [DEADLINE DATE - typically 10-15 días]. Payment should be made payable to [YOUR COMPANY] and sent to [PAYMENT ADDRESS]. Alternatively, payment may be wired to [BANK DETAILS IF APPLICABLE].

Consequences Paragraph

Consequences of Non-Payment
If we do not receive full payment by [DEADLINE DATE], we will have no alternative but to pursue all available legal remedies without further notice. This will include filing a demanda judicial in the appropriate California tribunal, where we will seek the full principal amount, all accrued and continuing prejudgment interest, reasonable abogado fees, tribunal costs, and any other relief to which we are entitled. A judgment against [DEBTOR COMPANY] will become a matter of public record and may be reported to credit agencies. We strongly encourage you to resolve this matter now to avoid these consequences.

📄 Carta de Demanda Completa de Ejemplo

Below is a complete carta de demanda template. Replace all [PLACEHOLDERS] with your specific information.

Complete Plantilla de Carta de Demanda
[YOUR COMPANY NAME]
[YOUR STREET ADDRESS]
[CITY, STATE ZIP]
[PHONE NUMBER]
[EMAIL ADDRESS]

[DATE]
VÍA CORREO CERTIFICADO CON ACUSE DE RECIBO
AND EMAIL

[DEBTOR COMPANY NAME]
[ATTENTION: ACCOUNTS PAYABLE / CEO NAME]
[DEBTOR STREET ADDRESS]
[CITY, STATE ZIP]
Re: FORMAL DEMANDA FOR PAYMENT
Invoice No(s): [INVOICE NUMBER(S)]
Amount Due: $[TOTAL AMOUNT DUE]

Dear [RECIPIENT NAME OR "Sir/Madam"]:

This letter constitutes a formal demand for payment on behalf of [YOUR COMPANY NAME] ("Creditor"). Despite repeated informal requests, [DEBTOR COMPANY NAME] ("Debtor") has failed to pay for [goods delivered / services rendered] as agreed.

BACKGROUND

On or about [DATE OF AGREEMENT/ORDER], Debtor engaged Creditor to provide [DESCRIPTION OF GOODS OR SERVICES] de conformidad con [CONTRACT/PURCHASE ORDER/AGREEMENT REFERENCE]. Creditor fully performed its obligations, including [BRIEF DESCRIPTION OF PERFORMANCE]. Debtor accepted [the goods / the completed work] without objection.

Creditor issued the following invoice(s) to Debtor:

Invoice No. [INVOICE NUMBER], dated [INVOICE DATE], for $[AMOUNT], due [DUE DATE]
[ADD ADDITIONAL INVOICES IF APPLICABLE]

Despite the passage of the payment deadline and our subsequent payment reminders on [DATES OF REMINDERS], the total amount of $[PRINCIPAL AMOUNT] remains unpaid as of the date of this letter.

LEGAL BASIS FOR THIS DEMANDA

Under California law, Debtor is obligated to pay for [goods accepted (Cal. Com. Code Section 2607) / services rendered]. California código civil Section 3287(a) entitles Creditor to prejudgment interest at the legal rate of 10% per annum on all sums due, calculated from the date each invoice became due. [IF APPLICABLE: Además, de conformidad con California código civil Section 1717 and the abogado fee provision contained in our agreement, Creditor tiene derecho a recover all reasonable abogado fees and collection costs incurred in pursuing this debt.]

AMOUNT DUE

As of [CURRENT DATE], Debtor owes the following:

Principal (unpaid invoices): $[PRINCIPAL AMOUNT]
Prejudgment interest (10% per annum through [DATE]): $[INTEREST AMOUNT]
[IF APPLICABLE: Late fees per contract: $[AMOUNT]]
TOTAL AMOUNT DUE: $[TOTAL]

Interest continues to accrue at the rate of $[DAILY INTEREST AMOUNT] per day until payment is received.

DEMANDA

DEMANDA IS HEREBY MADE that Debtor pay the total sum of $[TOTAL AMOUNT] within fifteen (15) days of the date of this letter, a más tardar [DEADLINE DATE].

Payment should be made by check payable to "[YOUR COMPANY NAME]" and mailed to the address above, or by wire transfer to:

Bank: [BANK NAME]
Account Name: [ACCOUNT NAME]
Account Number: [ACCOUNT NUMBER]
Routing Number: [ROUTING NUMBER]

CONSEQUENCES OF NON-PAYMENT

If Creditor does not receive full payment by [DEADLINE DATE], we will pursue all available legal remedies without further notice. This will include filing a demanda judicial in the appropriate California tribunal seeking:

  • The full principal amount owed
  • All accrued and continuing prejudgment interest
  • Reasonable abogado fees and costs
  • Tribunal costs and cuota de presentacións
  • Any other relief the tribunal deems appropriate

A judgment will become a matter of public record and may be reported to commercial credit reporting agencies, which could affect Debtor's ability to obtain credit and conduct business.

We trust this matter can be resolved without litigio. Sin embargo, we are prepared to take all necessary legal action to protect Creditor's rights. Please contact the undersigned immediately to arrange payment or to discuss a resolution.

This letter is not intended to be a complete statement of all claims, daños, or legal theories available to Creditor, all of which are expressly reserved.

Atentamente,




[YOUR NAME]
[YOUR TITLE]
[YOUR COMPANY NAME]


Anexos:
- Copiar of Invoice(s)
- Copiar of Contract/Purchase Order
- Proof of Delivery/Completion

💌 Sending Tips

  • correo certificado: Always send via USPS correo certificado with acuse de recibo Requested to prove delivery
  • Email Backup: Also send by email to the primary contact and accounts payable to ensure receipt
  • Keep Copies: Retain copies of the letter and all enclosures for your records
  • Track the Deadline: Mark your calendar for the response deadline and follow up promptly if no payment is received

👥 Cuándo Contratar a Collections Abogado

Collecting unpaid invoices requires balancing collection costs against the debt amount. Here's when self-collection makes sense versus when professional help improves recuperación.

✅ Puede Manejarlo Usted Mismo Cuando:

  • Invoice under $10,000 with clear documentation
  • Debtor acknowledges the debt and ability to pay
  • Small claims tribunal is an option (up to $12,500 in CA)
  • Debtor is local and assets are known
  • No dispute about scope or quality of services

⚠️ Contrate un Abogado Cuando:

  • Debt exceeds $25,000
  • Debtor disputes the invoice or quality of work
  • Debtor is out of state or overseas
  • Company may be insolvent or restructuring
  • Personal guarantees may need to be enforced
  • UCC lien filing or mechanic's lien needed
  • Debtor has counterclaims or threatens litigio
  • Multiple invoices or complex account history

📊 ¿No Está Seguro Si Necesita un Abogado?

Collection costs should be weighed against potential recuperación. Take our free assessment to determine the most cost-effective approach for your situation.

Tomar Evaluación Gratuita →

🚀 Próximos Pasos

Qué hacer después de enviar su carta de demanda.

Cronograma Esperado

Días 1-3

Debtor receives and reviews your carta de demanda

Days 3-10

Debtor consults with management, reviews their records

Days 10-15

Response expected: payment, payment plan offer, or dispute

Si Pagan

Verify the payment covers principal plus interest through the payment date. If the payment is short, send a brief letter acknowledging receipt and demanding the remaining balance.

If They Offer a Payment Plan

Consider whether to accept. If you agree to a payment plan, document it in writing with clear terms including: payment amounts, due dates, consequences of default, and whether interest continues to accrue. Consider requiring a personal guaranty from the business owner.

If They Dispute the Debt

Review their claimed defenses carefully. Common defenses include claims of defectuoso work, failure to deliver, or disputes about contract terms. Gather your evidencia and consult with an abogado about the strength of their defenses versus su reclamos.

If They Don't Respond

  1. Tribunal de Reclamaciones Menores (Up to $12,500)

    For claims up to $12,500 (increased from $10,000 in 2024), California Tribunal de Reclamaciones Menores offers a fast, inexpensive option. No abogados allowed, but you can represent your business. Filing fee is typically $75-$100.

  2. Limited Civil Tribunal ($12,501 - $25,000)

    For claims between $12,501 and $25,000, file in California Superior Tribunal, Limited Civil division. Simpler procedures than unlimited civil.

  3. Unlimited Civil Tribunal (Over $25,000)

    For larger claims, file in Superior Tribunal Unlimited Civil. Consider hiring a commercial litigio abogado. Many work on contingency or hybrid fee arrangements for strong collection cases.

  4. Collection Agency

    If litigio is not practical, consider assigning the debt to a commercial collection agency. They typically charge 25-50% of amounts recovered but handle all collection efforts.

⚠ Watch the Prescripción

  • Written contracts: 4 año(s) desde when payment was due (CCP 337)
  • Oral contracts: 2 año(s) desde when payment was due (CCP 339)

A carta de demanda does NOT toll (pause) the prescripción. If your deadline is approaching, file suit immediately to preserve sus derechos.

¿Necesita Ayuda Legal?

Complex collection matters or large claims often benefit from professional legal guidance. Get a 30-minute strategy call with an abogado to evaluate su caso and options.

Agendar Consulta - $125

Recursos de California