<p>Ah, OP, I fear you have just learned one of life’s hard lessons: make sure the paperwork’s in order (yours AND theirs) before beginning work. Document thoroughly, keep copies (dated) of all work submitted, and, for heaven’s sake, don’t keep providing work on an ongoing basis when you haven’t yet been paid for earlier work.</p>
<p>I am really sorry this happened to you, and I know $1500 seems like a lot of money to you at this point, but my advice is to chalk it up to experience in the school-of-hard-knocks, and move on.</p>
<p>I think your cost (time, money, aggravation) in pursuing this would be very high, and I don’t have much confidence you could win.</p>