My final payment was due on or around April 17 2023- the client stated becoming unreasonable after we fixed an item that was initially done incorrectly. We had a field rep from the product come out and say that we did everything in our power to resolve it. The remaining balance was kept in limbo by the homeowner even though he promised, we would be paid after that. He started coming up with all these nitpicking things that would fall under my warranty. However, I told him I would not fulfill any warranty work until the full payment was made. What do I do?