Do these now, no lawyer required
- Gather and organize every document in one place: contract, addenda, receipts, transfers, bank records.
- Put any further requests to the developer in writing, and keep copies.
- Stop sending new payments, and don't sign anything new under pressure.
- Write a plain timeline: what was promised, what you paid, what happened, and when.
- Request copies of your own paperwork from anyone who holds it.
- Treat it as time-sensitive, because deadlines may already be running.