Paypal REFUSES to fix THEIR problem they caused

STORY: A fraudulent ebay seller bought a laptop from me then wanted a refund, but i DO NOT accept refunds, so paypal desides to take out $50 that i don't have in my account so my balance is NEGATIVE, and ebay only refunded me $10.80 and i'm STILL negative, then someone buys something from me, and since i didn't get my money because my balance is negative because of an unauthorized transaction, i can't refund the guy because my balance is negative, so that second buyer basically burned his money. i contacted ebayu and they have yet to respond.