@Nocutenamesleft
It is theft!
Theft is explained as to deceive someone
The dishonest appropriation of property.
So ring the police.
It may be 'low-level crime,' but this may not be a bad idea actually....... This woman may have done it before, and will probably do it again. Calling the police, and having them contact her about it, may make her think twice about doing it again, and her card will be marked.
A man screamed in my neighbour's face 2 months bac, in Tesco car park, as she was in a child zone with her blue badge. (There were no disabled spaces.) It shook her up terribly and frightened her. It was her word against his, but she (on my advice) called 101 and reported him. Luckily, she took his car reg as he walked off ...
Long story short, the police took the details off her, and came back a day or two later, and said they had looked into him, and they had had a report into him and his aggressive behaviour towards women in public 2 months earlier.
It was that woman's word against his then, so they just kept it on record and didn't do much, but (said the PC) because a second report had come in about the same man being abusive in 8 weeks. She gave a statement, and he is in court in February, on a charge of affray and aggression (or something similar.)
Even though it seems trivial (the OPs issue,) it may be worth reporting it, as this woman may have stolen off people before. And it IS theft, £10, or £100, or £1000, it's STEALING, and the last time I checked, stealing from someone was against the law.
As pps have said, report her to facebook/facebook marketplace too. Not sure how, but there has to be a way to do it.
Ignore the 'chalk it up to experience' comments. Why should this cheeky f*cker get away with it?