Well this is unexpected. Just recently I'm helping this guy to resolve his problem but it went even worse when this possible accounts has been added. Anyway, nice catch @Veleor, but we still need to prove it.
I see a lot more accusations coming into your way. If you are clean then I do not see you have anything to be worried. You can start with proving the PM was correct. Find any DT and give them your account credentials to check the PM authenticity. If you pass then you can resolve the rest.
I do not have any problem to share my login credentials for mod or with most trusted DT member to check and verify it bro. Hope this would be resolved and I am seeing this person lapongetiasuu trying to troll me in his multiple accounts I guess. Then UMERIDREES noted alt of made post on this thread and the timelord's thread. I have snipped and complained there itself.
Well OP, to prove that the conversation you had with that extortionist is real, then I will be waiting for the result of this. Also, @mdayonliner is not a DT but I trust him as well. You can safely entrust your credentials to him just to verify that the conversation were real.
OP looks like you have two cases to prove..
1. The conversation with the extortionist.
2. Those possible alt accounts of yours.