I would do everything possible to try to resolve it, then I would resort to posting all information on here so it doesn't happen to anyone else.
I'd take it to a civil level, hunt them down and "RESOLVE" the matter in a much more "personal" mannor. I have zero tollerance for liars and thieves.
DISCLAIMER:
I'm not saying for you to do this, this is just what I do when I get screwed.