I have reviewed several cases similar - being granted access to all involved parties dm's - even when some were deleted by one of the involved parties (if one side is deleted but the other side kept it, then they are still there) and what is the same each time is this:

1. person being scammed receives a dm with a link that appears to be a thread in the forums
2. user receiving the dm clicks the link - gets a page that "looks" like forums and requires them to re-log in
3. at this point user has just given their pw to the scammer
4. scammer agrees to use escrow
5. scammer sends message from hacked account to escrow to release funds
6. scammer gets paid
7. user gets nothing
8. escrow gets blamed

This is not the fault of the escrow. maybe it could be solved if the escrows require a signed message from the buyer before releasing funds - for the scammer to do that would require that they also compromised the buyers private keys.

The problem here is that many users sadly use exchange accounts or dont know how to sign a message.