Ive got one exactly the same at the minute.
Contacted me via email, agreed a price. I turned up she watched me clean the entire house and she said she would pay online.
No payment after two weeks, no replys to texts and hasnt answered the door thus far.
Absoloute scum, what kind of person does this? Ive thought exactly the same mate, what revenge can i carry out, but then you think what if cctv or neighbours see or shes in etc.