JMO you have nothing to lose by appealing their decision -

To appeal a case you've lost, find your case details in My eBay and select Appeal from the More actions drop-down menu.

Appeals

Buyers and sellers can appeal by providing appropriate documentation within 30 days from when we make a decision about a transaction issue.

I would also bring into play your return policy stated in the listing:

i accept returns for items received faulty and DOA only.
I cannot accept returns for change of mind, incompatibility issues or items purchased in error.