If you are from the United States, this is a very easy thing to enter into the legal system with justified results that eBay will work with. This is a group of people within eBays' Trust and Safety Department that will see if the person who left you the negative actively sells the same item as you have, in which case you can get the negative removed, and reinstated the fees and even the item or its cost. Failure to rectify these situations on eBay's end means you can more easily target eBay in a legal dispute.
Random fact:
Many large corporations actively purchase items from people who sell their items way below their retail value on eBay consistently, even if their items are legitimate and purchased from a licensed distributor simple to leave them negative feedback and to have them forced off of eBay and Amazon, by lying about the service and the legitimacy of the item being a knock off or not. These are also the same people that seek out sellers of licensed and trademarked items that send out VeRO notices to eBay, and/or purchase the items and send their contact information to legal departments for small finder fees.