Do as Peerless suggests & contact your bank etc. They probably have a set procedure to follow in cases of fraud.

Some members have managed to get refunds from these scammers, there's a lot of info in this thread
http://www.gnutellaforums.com/showth...threadid=44499

Keep in mind, if you decide to pursue matters directly with the scammers, you'll have to be prepared to put up a fight. They can be very intimidating.