You call your bank, you say it was an unauthorized payment. Instant reversal.
Don't be fooled. The only thing that can't be reversed is a Claim&Cancel when not paid by credit card. Bank's can't even re-do that shit.
But a credit card can. Credit Cards can go strait through Gift (Which Banks can too) and through C&C
Follow one of the stickies in this forum: Limit your paypal to never accept CC payments, and MAKE them do C&C instead of Gift. Gift is ALWAYS reversible if funded by a bank.
Don't believe me? Try it. I used to sell WoW accounts on MD and got recalled a 300$ payment for one. Gifted, was a stolen paypal funded directly through bank (Because my PP doesnt allow CC payments).
Instantly stopped doing gift after that point. I think it messes with paypal and makes you look shady if you C&C every transaction, but it's been 6 months of every transaction like this without any repercussions.