Always check and see if the item you bought is as described (e.g. if it has any marks that weren't mentioned, etc). If it isn't, contact the seller and let them know – politely. Most sellers are eager to ensure you're happy because they don't want negative feedback, and will be happy to give you a refund or a partial refund. eBay has a money-back guarantee so if you receive no reply from the seller, you can open a case in the resolution centre and eBay will ensure you get your money back.