Scammers done waste their time reversing THROUGH PAYPAL, they use their time wisely and reverse THROUGH THE BANK. Once the bank reverses the transaction, paypal honestly has no choice but to simply refund the money. Aside from this method, a lot of scammers are actually using hacked bank accounts. So if you are selling Bitcoin on paypal, most of the time you are actually receiving a payment NOT from the original paypal account holder. So when the reversal comes in, its actually usualy not even the scammer, its someone that realized their paypal account was hacked and made a purchase. Its very hard to tell in this circumstance but either way you are shit out of luck to be honest.