Demand Letter for Paid Work

I need a demand letter drafted to address a situation with a programmer.

Here are the specifics:
- The programmer received payment but has not delivered the agreed-upon work.
- I have already communicated my concerns multiple times without resolution.
- I have all the necessary documentation and communication related to the project.

Ideal Skills and Experience:
- Experience in drafting legal demand letters.
- Familiarity with contract law in the USA.
- Strong communication skills

I'm looking for someone who can draft an effective demand letter to help in resolving this issue legally.