For collection items, the buyer should bring with them a 6 digit QR code which you scan or add tthee numbers manually alongside the order details >> Confirm Collection.
Message the buyer to look through their eBay messages / order details to find this code to send to you.
If they don't then your payout will be held for 14 days.
Foe any future collection items send the buyer a polite message reminding them to brig the code as the item won't be released without it.
The code is your only proof the item was collected.
@alesstorm