If you can prove that - then it's very likely that the accusations about you in this thread can going in different direction. But you don't even prove anything here other than just pretending that the two of you are partners on one of the sites, that's too convoluted for your defense. I believe that every trading transaction between two users has a chat history about fees, price and how to do it, it's not as easy as you send it to the exchange. So I'm sure you do too before the transaction - even the last one, then things could be different.

So why don't you prove it?
Don't say it's also private - this doesn't seem like the right time.