Yeah, good advice from koshkaj to only send deposits to SPs that have multiple good reviews here, especially if they are recent too, as people can switch up over the years.
If you don’t mind the old bill knowing your sexual business, reporting her contact details or any info you have on her to the police is also a fair next step as puntingpro1 said. If it was £10-50 I’d be inclined to leave it and maintain my privacy but the price of nearly an average agency punt is criminal. Only send hundreds to an SP once you’ve seen her in person a few times
It’s probably best OP if you counteract such a bad experience and visit a well reviewed SP who fits your criteria.