Paid $5K Retainer to Attorney Who Did Nothing — Wants to Keep It

I publish illustrative scenarios prepared by my practice. All participants and conversations are fictional. The fictional posts are not posts by real users, accounts of client experiences, or reports of actual results.
Illustrative scenario prepared by my practice.
For informational purposes only. This is not legal advice.
Hypothetical question

Looking for advice on this situation. Paid $5K Retainer to Attorney Who Did Nothing - Wants to Keep It What would you do?

Details: I'm in a situation where I need to understand my legal options. Has anyone dealt with something similar?

Illustrative response

The merger/integration clause is the most dangerous clause in any contract. It says the written contract is the ENTIRE agreement, wiping out any verbal promises. Always get verbal agreements in writing before signing.