Damn, the title sounds like some BSDM movie!
One thing that struck me:
It wasn't up to 10 minutes after he contacted his bank I received the payment in my account.
I don't believe that the bank was someone able to solve and transfer your money the balance reflect in your account in 10 minutes after not being able to do in 2 days, you said he had proven that he had sent the payment with documents, by chance can you compare the proofs with the current transfer as I tend to believe that as in many cases he didn't pay at all the first time and only under pressure and maybe because of a good fluctuation in exchange rates he agreed to do so!
[Yep, this has to be written more often, since I fear that the people used to CEXs can a bit too easy make mistakes and then blame and avoid P2P, and return to CEX, give their ID to everybody and so on, when P2P exchanges should be the norm.
In this situation:
CEX - the CEX, their bank, your bank, you
P2P -the P2P platform, the other guy, the other guy bank, your bank, you
A bit two many peers above 2!