You can try what I did. I filled out a Mail Fraud Report form from the USPS. That is, if you sent the payment via mail and it crossed state lines it becomes a federal matter. The person, a CEGer who will remain nameless at this point, found out and paid me back right away. I don't hold any hard feelings or grudges, and I was happy to get my money back, but it didn't sound like anything was followed up on my the Mail Inspectors office. With that said, its all I can offer to help.
How did you pay?