12-11-2017 9:10 PM
Simply open an unpaid item case, run it for 4x24 hours timed to the second the case opened. Sometime on day 5 of the case you will see on the case screen the option to get a fee credit - close the case at that point. Buyer gets a strike and you can relist the item.
https://resolutioncentre.ebay.co.uk/
Ignore everything the buyer might say - you only get 1 case per transaction and closed cases cannot be reopened.
Add their id to your blocked bidder list to prevent them returning.