I just had a similar thing happen to me. Some chiseler was selling a Marlin 39a at a very good price, and I jumped on it, minutes after he posted. He emails me and says its mine and he needs an FFL to send it to and shipping would be $25. So, I drive over to the local pawn shop and pay the transfer fee of $25, get a copy of the FFL, scan it and email it to him, asking for payment instructions. No answer for a day, during which I go get a PO M/O. 30 hours after he told me its mine, he gives me some cock-n-bull story about how he had it listed elsewhere and someone had an earlier time stamp.
The deal was so good, I'm not surprised he reneg on me, but I'm out the transfer fee, that I may be able to whedle out of the pawn shop guy, not to mention all the time it takes to get the thing and then go plead for my money back.
The kicker is that it took him 30 hours to respond to my email asking him for an address to send payment, but took him 5 minutes to respond to my post calling him a bad dealer and refusing to reimburse me for his error. Piece of garbage.