BUYER NEVER PAID FOR ITEM THEN WHEN DISPUTE WAS INSTIGATED HE PAID BUT LEFT NEGATIVE FEEDBACK

[plpmr]

one way or the other a buyer has the legal right to cancel for any reason and you have to accept because your buyers have virtually unlimited rights as you are a business seller trading as a private seller.

Also, your reply to the neg and the false positive[s] you left can be removed if the buyer[s] complain to eBay.