When leaving feedback after buying an item, and you are not happy with it, you must contact the seller to arrange an agreement first.
Myself I sell car performance chips (resistors) on ebay, and have got a couple of negatives from some buyers. If a buyer leaves me neutral or negative, I will do the same which then is not good for them or myself. These people never contacted me in the first place about getting a refund, if they did they would have done. Alot of new ebayers do this as they dont know how ebay works. So please next time your not happy with an item, CONTACT the seller first