[SU NOMBRE / NOMBRE DE EMPRESA] [DIRECCION] [TELEFONO / EMAIL] [FECHA] VIA EMAIL AND CERTIFIED MAIL Return Receipt Requested [NOMBRE DEL CLIENTE] [EMPRESA DEL CLIENTE] [DIRECCION] Re: Demand for Payment - Additional Services Rendered Beyond Original Scope Original Agreement: [FECHA] Amount Due: $[MONTO] USD Dear [NOMBRE]: I write to demand payment for professional services rendered to [EMPRESA CLIENTE] that exceeded the scope of our original agreement dated [FECHA] (the "Agreement"). I. ORIGINAL SCOPE Under the Agreement, I was engaged to provide [DESCRIPCION DE SERVICIOS] for a fixed fee of $[MONTO]. The scope was specifically limited to: - [ITEM 1 del SOW original] - [ITEM 2 del SOW original] - [ITEM 3 del SOW original] - [X] rounds of revisions included A copy of the original Statement of Work is attached as Exhibit A. II. OUT-OF-SCOPE WORK REQUESTED AND PERFORMED During the course of the project, you requested numerous additions and changes that fell outside the agreed scope. Despite my notifications that these requests constituted additional work requiring separate compensation, you insisted the work be completed and I proceeded in good faith. The out-of-scope work includes: 1. [FECHA]: [DESCRIPCION DEL TRABAJO EXTRA #1] - Your request email attached as Exhibit B - Hours spent: [X] hours at $[TARIFA]/hour = $[MONTO] 2. [FECHA]: [DESCRIPCION DEL TRABAJO EXTRA #2] - Your request via [SLACK/EMAIL/CALL] documented in Exhibit C - Hours spent: [X] hours at $[TARIFA]/hour = $[MONTO] 3. [FECHAS]: [X] additional rounds of revisions beyond the [X] included - Revision requests documented in Exhibit D - [X] additional rounds x $[MONTO] per round = $[MONTO] 4. [OTRAS PARTIDAS DE TRABAJO EXTRA] III. PRIOR COMMUNICATIONS I informed you on multiple occasions that this work was outside our agreement: - On [FECHA], I sent a change order for $[MONTO] for [DESCRIPCION]. Your response was [DESCRIBE - approved, ignored, rejected but work demanded anyway]. - On [FECHA], I notified you that revision round [X] exceeded our agreement. You acknowledged but insisted I proceed. - On [FECHA], I sent an email explicitly stating: "[QUOTE DEL EMAIL]" Copies of these communications are attached as Exhibits E, F, and G. IV. LEGAL BASIS You have received the benefit of my professional services without paying fair compensation. Under the doctrine of quantum meruit, I am entitled to recover the reasonable value of services rendered. Additionally: 1. IMPLIED CONTRACT: Your requests for work, combined with my performance and your acceptance of the deliverables, created an implied contract for additional compensation. 2. UNJUST ENRICHMENT: You have been unjustly enriched by receiving services valued at $[MONTO] without paying for them. 3. PROMISSORY ESTOPPEL: [SI APLICA] On [FECHA], you stated "[QUOTE]" which I reasonably relied upon in performing the additional work. V. DEMAND I hereby demand payment of $[MONTO TOTAL] within ten (10) business days of this letter, calculated as follows: [TABLE DE CALCULO] - Additional development hours: [X] hrs x $[RATE] = $[MONTO] - Extra revision rounds: [X] x $[RATE] = $[MONTO] - Rush fees: $[MONTO] - Tools/licenses purchased for project: $[MONTO] TOTAL DUE: $[MONTO TOTAL] Payment should be made via [WIRE/CHECK/PAYPAL] to: [DETALLES DE PAGO] VI. CONSEQUENCES OF NON-PAYMENT If payment is not received by [FECHA LIMITE], I will: 1. Initiate [SMALL CLAIMS / CIVIL LITIGATION / ARBITRATION] to recover all amounts owed plus: - Pre-judgment interest at the legal rate - Court costs and filing fees - Attorney's fees if recoverable 2. Retain all intellectual property rights to the additional work performed until payment is received in full. 3. Pursue all other legal remedies available. VII. PRESERVATION NOTICE Please preserve all documents, emails, messages, and files related to this project. Destruction of evidence may result in sanctions. I trust this matter can be resolved amicably. However, I am prepared to pursue all available legal remedies if necessary. Sincerely, [SU NOMBRE] [CARGO/TITULO] Exhibits: A - Original Statement of Work B - [Email requesting extra work #1] C - [Documentation of extra work #2] D - [Revision request communications] E-G - [Communications re: out-of-scope work] H - Time tracking records I - Invoice breakdown

Subject: STOP WORK NOTICE - Scope Change Authorization Required Dear [NOMBRE], This notice is to inform you that I am pausing work on [PROYECTO] effective immediately pending resolution of outstanding scope and payment issues. REASON FOR STOP WORK: The project has expanded significantly beyond our original agreement. Specifically: 1. [LISTA DE CAMBIOS DE ALCANCE] 2. [TRABAJOS ADICIONALES SOLICITADOS] 3. [REVISIONES EXCEDENTES] These additions represent approximately [X] hours / $[MONTO] of work beyond our contracted scope. CONDITIONS TO RESUME WORK: Before I can resume work, I require: 1. Written acknowledgment that the items above are out-of-scope additions 2. Approval of Change Order #[X] for $[MONTO] (attached) 3. Payment of $[MONTO PARCIAL] representing [50%/partial payment for extras already completed] I remain committed to completing this project successfully and delivering excellent work. However, I cannot continue to absorb the cost of scope expansion that was not contemplated in our original agreement. Please respond within [3-5] business days to discuss how we can move forward. Best regards, [SU NOMBRE] Attachment: Change Order #[X]