I think the only way to get your FVFs back is when a buyer requests the cancellation?
When sellers do any kind of refund that was not first communicated through the eBay message system the seller gets an out of stock defect for the transaction even if it was a partial refund after the buyer receives the item.
If you do not want to ship this item I would communicate with the buyer through the eBay message system and ask them if they want to cancel the sale because of the mistake buying something they are not familiar with. IF they reply back and say yes, you can cancel and gets your FVFS back. I am not sure there is any other way?
Good Luck Selling!
