anybody had a problem with fake bidders

I have being trying to sell my car on ebay for last month. I was forced to list it twice and both times the winning bidder did not contact me. I cannot leave negative feedback to those bidders because ebay does not allow it. Ebay sucks. I would never sell anything on ebay again. These fake bidders are used car dealers who create multiple fake accounts and bid on private sellers cars, with no intention to buy.They do that so people would buy their cars instead. EBAY NEEDS TO DO SOMETHING ABOUT THIS.I phoned ebay and they are obviously not interested in doing anything about fraudsters who have infected ebay.