First off, your final value fee will be refunded by Ebay if you refund the money. http://pages.ebay.com/services/buyandsell/finalfee.html

It would seem that your description was fair, and I don't think it would be terrible for you to not issue a refund. I also don't think it would be terrible for you to issue a refund less your expenses.

On the other hand you might want to consider that our code of ethics provides for a return policy unless the sale or trade is specifically made excepted from the return policy.

I know this wasn't a chip and our ethics code is not binding, but the point is that if we think this is fair and ethical in a chip transaction maybe we should give some thought to why this is and why this shouldn't apply to all the things we do in life.