For the item sold but not collected, you needed to cancel the order first before relisting.
For collection, buyers pay at eBay checkout, cash on collection no longer allowed, and they are given a 6 digit QR code.
It is essential for them to bring and give this code to you to scan or manually enter those numbers, as this is the only proof that item has been collected, and it finalises the transaction.
It is advisable not to part with collection items, until in possession of that code. There's no other way to mark it as collected, and you can leave yourself open for the buyer to open a case for item not received.
@nelson8217
