Hi simon4,
Contact your bank/CC company & cancel the transaction. You can report it to their fraud department, too. Some people recommend cancelling the card altogether, check it out with your bank.

Page 1 of this thread has advice on how to deal with these scammers. Here's another thread with advice on how to get a refund from scam sites:
http://www.gnutellaforums.com/showth...threadid=44499

Good luck