You have 2 choices. If you agree to cancel the sale, you can send a mutual cancellation request which they need to accept for you to get your FVF back.
http://res.ebay.co.uk/ws/eBayISAPI.dll?ResolutionCenter
if they dont agree to it or decline, you will be charged. Both sides can leave feedback If they dont respond to it, close yourself after 7 days
or
If they havent paid, open a UPI after 4 days and close 4 FULL days later. They get a strike on their account, you get your fees back. Neither side can leave feedback