I had a nasty experience with paypal earlier this year.
A guy in Austria bought a TALAS 36 RC2 off me. He paid for the slowest possible shipping and then reported an unreceived item when it didn't arrive promptly. However, as time went on he stopped responding to my emails and those of paypal.
This didn't stop paypal taking money out of my account though! Despite the fact that the buyer would not answer paypal's own emails asking if he had received the item, they debited 605 from my account.
The buyer obviously was smart enough not to commit to writing in an email that he hadn't received the fork as that would be irrefutable evidence of fraud.
I'm aware there is an implied duty on both parties to a contract to act reasonably. I also believe there is a duty of utmost good faith on the part of Pypal as they are effectively holding money on trust.
I've written to them and I am going to stick in a small claim against them. I think I might have them on the basis that they debited the money when the buyer was refusing to confirm whether or not he received the item and that is unreasonable.