The problem is that you as seller are only protected if you send to address provided. Sending to any other address and buyer could open a not received case.
When buyer pays they should check that delivery address is correct and if not edit BEFORE paying. Therefore only way is to end and buy again, even if only to protect yourself.
Simple postage does not help, anyone would think sellers are incapable of dealing with buyers, as has happened in the past, before ebay started thinking they know best.