Contactless payment issue

[Discobooloo]

Hi
I was in London on Friday and saw a genuine stand selling poppy pins, so I did a contactless payment for one for £5.
I noticed on my bank statement today that the £5 went out ok but a further £10 went out today. It's location also says London.
My friend used the contactless machine straight after me for £5 and only that has left their account (nothing is pending).
I'm not concerned about the £10, but how this could happen and do I need to be concerned?
My bank won't help unless I contact the charity and ask for a refund and then wait 15 days.
Does anyone have any insight please?
Do I just write it off? Do I need to cancel my card?
Thanks

Freeze your card asap. Then contact your bank and inform them. The bank will block your card and issue you a new one

Were both transactions definitely to the same place or did you buy other things or use an atm while you were there?

Thanks.

Yes, I have frozen the card. Like I said, bank were not interested when I spoke to them tonight.. Said I had to contact the merchant and then wait 15 days if they won't refund. I'm not bothered about the charity having £10, more how it could happen and have I been compromised.

Both transactions definitely to British royal legion, same as my friend's. Only used my card contactless on the tube and all payments gone out ok.