So the buyer returned and got a refund for a NAD item that you sold them. Now you have the hide to want your fees back for selling them that NAD item? If i was the buyer i would decline a cancellation offer and leave you a neg. It seems the item arrived within 24 hours, she noticed it was not As described and opened a dispute. The buyer has the right to do this dont forget.

By refunding you have admitted the item was NAD. Now why should ebay give you your fees back? As far as both ebay and PP would be concerned you were in the wrong.