One of my relatives bought my Dad a pair of M&S pyjamas for Christmas. They were Small and my dad is not small. She did not put the receipt in the parcel.
I took the unopened pyjamas back to M&S, without a receipt. I was given a credit note for £25.00
I could have gone into M&S, picked up a 'packet of pyjamas and taken them to the till to be given a credit note.
There should be some kind of electronic something that says that the item has previously been paid for.