I went through some PM's and verified with someone and I think @Developer did lost his telegram access. So I have removed my feedback.

At this point you both are not trying to bend to solve the issue. Deal being public or private isn't a problem. It would be same problem even if forum accounts get hacked in middle. How would you verify he is the same? I suggest at this point you stake your address (if not staked) and carry over your deals with messages signed from your BTC address. That is what I think is safe way to conduct now.

I am done with this issue and its all upto both of you now.