So I do this, lose patience and exchange with him through Mastodon, I know he looks at it (not like his emails) and if he does not answer it's because he ignores me. I also tell him that either he refunds me EVERYTHING, I don't want credit this time, or I change provider and report him to the law for scamming.

He agrees to reimburse me for one bill, but not the last tax of 36.18 EUR, he plays dumb and every time I ask him he tells me he'll look into it, but then doesn't contact me again.