Look at it this way: Did you learn anything?
Business involves a certain amount of unplanned pro bono work. Sometimes it just happens. Imagine how many business deals went south when Katrina hit.
Sometimes a deal gone bad is the result of doing business with people who never intended to pay you in any event, maybe because they didn't have the funds to start with or maybe it was because that's their approach to doing business.
If you are going to be self-employed you really need to be a good judge of character and you also need to turn down work when your instincts tell you to.
Learn the lesson and move on. Focus on making money and marketing.
SOBs are already paying the price for their ill nature. Trust me on that. They already live in a world where no one is to be trusted, eveyone is a dupe, love is a word and so on. A hearty SOB will laugh at your efforts and a darker one will sue you for libel and claim your did lousy work.
Claim the lesson without cynicism, admit your role in your plight, have a good cry and a good laugh at yourself, and move on.