I'm not sure, but I don't think the seller scammed OP. If he was willing to scam him and run away with the money why would he send him the user credentials in first place!
I believe the Cryptios or the forum software locked the account because of suspecious activities.
Here is a similar case:
Well spotted! It appears that
this account has indeed changed hands as the email address was changed on July 22, 2017, alongside with posting and IP patterns. I've now locked it! In the meantime, DT members can go ahead and paint it red until (and if) we determine the real owner.
Thank you for bringing this up!
OP shot himself in the foot by exposing the bought account instead of claiming it back.
Has justice been served?!