The woman on the turnstile wouldn't let me in even when I explained the situation. So she went off and got a scanner to take my package. She didn't offer a receipt, and when I asked for one said it wasn't possible to give me one. I checked my email, and nothing there either. So I had no evidence I'd actually returned my item and she just said something like "It's in the system and never makes a mistake" or some similar rubbish.
While I was in there I saw several people walk just inside, faff around on their phones for 5 minutes then either give up or eventually get past the turnstiles. There's literally no benefit for customers unless you're shopping at busy times.
So all in all an unmitigated disaster.