As others have said, you made the wrong move in appealing because in this particular case, how could you prove to ebay that the goods were NOT discoloured? Ebay cannot see them and would side with a buyer in this sort of circumstance. We can't tell either.
Your best bet would have been to issue a return label immediately and accept the return.
It sounds to me that you went into an appeal first, you lost and ebay automatically awarded the buyer the refund. They probably did add that the buyer could keep the goods because at that stage, you had not issued a return label?
If I have the sequence right, you may as well accept you've lost the goods and the money. This buyer does not like you, you challenged their claim and now (in their eyes) you are harrassing them over a case ebay has said is closed and an item ebay has told them they can keep, they need to do nothing more about etc
They have absolutely no intention of sending it back so yes, as someone else said, at least cancel the postage label and get your money back on that. And don't waste any more time messaging the buyer, they will just see it as annoying.
