I think it has happen to a lot of us.
I had a deal that I was to get one cheap card and some money. As he was sending the card he added the money. He did not have PayPal account. I recived the padded envelope ripped it two then taped back together. (poorly). Ripped through the PO label. The money was gone but the card was still there. The member got a person he know to send me the money by PayPal. (total amount) I was willing to spilt it with him but he said NO. I did send him some more cards trying to make it right wiith him.
PO stated there was nothing they could do about it.