My dad's friend did that many years ago, when he was called out in his 109 breakdown truck to a guy who'd driven his car into a ditch.....pulled him out, asked for his payment and the guy said
"na, sod you I'm not paying you, well you pulled me out now!"
My dad's friend replied "oh ok, it's like THAT is it?"
"yeah it is, what you going to do about it?"
So he got back in the 109, reversed, pushed him in the ditch and drove off....
he'll probabaly pay up next time!