Same happened to me a few years ago when i sold a xbox. Paypal refunded the guy 120 pound and put my account into minus. They just didnt want to no so I just ignored all there requests that i must pay money into my account.
They then sent some dodgy debt collecting company called nco after me. They tryed to get the money back by phoning me on a dailey basis sometimes 5-6 times a day and were saying that somebody would be coming around my house which of course never happened.
I kept telling them to take me court over it but nothing ever happened and my credit report was not affected let alone searched by them. They just used scare tactics and had no power to do anything. Ebay is a rip of these days. I was going to advertise something the other day until i realized they charge 10% on what you sell thats not including the charges from paypal which again is ebay owned.