So. I definitely had no £10 notes I could have paid for my £9.10 movie ticket with. I gave the girl at the desk a £20 note and 10p coin, and she handed me back a £1 coin. Being a little bit spacey, and distracted by my friend, I left the building with my tickets to get snacks from the shop across the street - before I realised I had been shortchanged.
I went back in, and asked politely if she could check the till - I said it was fine to check it, because obviously I know to be as polite and accommodating as possible to avoid coming off as a scammer. They took the cash drawer away and counted it, and said it came back a couple of pounds under, not £10 over. I was totally confused, and left them my name and number while I went to watch my film so I could come back afterwards and see if a second or third till-check came out differently.
When I returned after the film, they said the manager had counted it twice, and it was £1 under. No sign of my missing £10. I expressed my disappointment, reiterate the facts about the no money in my wallet beforehand, and only £20 notes from the ATM, but I only got a weak apology and a shrug. I gave up. Nothing I could do.
My friend says he bet the teller pocketed the £10. I like to try and think the best of people, but I just can't think where it might have gone, otherwise. And it's not like you can accuse someone of putting your money in their pocket - there's no way to prove that any money they had on their person was from the till, and you come off looking like a scam artist.
I'm keeping the faint hope that something turns around for me and they give me a call and say "hey, got your tenner here!" ...but I very much doubt it.