Dude... for fuck's sake. Just give him back the 210€. You wasted, in combination, probably days on this bullshit. Days you could have used to deliver newspapers and gain more than the 210€ in question. But instead, you chose to waste potentially thousands of € by arguing in a non-case.

Give him back his 210€, so we can finally end this ridiculous shitshow here and move on.

edit: sorry, language. But I have no idea how to put it more friendly.