Not much you can do about it now. You're lucky you weren't put down as a runner. Kudos to the girl.

What you could have done, as soon as you realized it, was to contact the shop. Even if you couldn't remember the name, they had a booking sheet where they could have looked up your booking on the day. Subsequent days are not good as it's handed in at the end of each night. Subsequent days aren't good to ask MLs directly as they tend not to know who was on roster.

You could have done more for sure. Next time (and unintentionally, it may happen again), just use this experience for making sure the girls get the money that you agreed to pay.