That's all pretty amusing. I'm always amazed that people are taken in by these scams.
We had someone steal a cheque from our office, and they tried several of these scams, where they'd use forged cheques on our account to 'overpay' for things, and then ask the seller to refund the money. It was fairly bizarre, and a major pain in the ass. But still, if someone 'overpays' you by $12,000, wouldn't that set off an alarm bell in your head?