I bought a mobil home the man promised to make repairs and now after he got the money he want fix

i paided a man 12000 dollars for this home and it needed repairs he put it in writeing and now he want fix it what should I do

That's what civil courts are for. Sue him. Take photographs of what was supposed to be fixed, keep all of the reciepts and documents. You have to be able to prove your damages. Either pay somebody to fix it and use their bill as proof of damages or get estimates of what it will cost.

Think about what he's going to say in court and be ready to respond.

If the amount of money is considerable, I'd hire a lawyer.