Scam?

[2012startovertime]

I sold an expensive item and the buyer who had contacted me about it paid. I got a message from a completely different buyer telling me that he had bought the same item from a different account and could I cancel it and relist it to help him with accounting issues. Of course, I smell something fishy and without tipping my hand ask the buyer who paid if he has a separate account and he says he does not. But the person who says that he wants me to cancel and relist it keeps contacting me. Has anybody ever had this happen to them? It almost sounds like he wanted to purchase this and wants the other person to be canceled so that he can then purchase it.