I’m trying my best to follow along here. It sounds like a very odd situation!
Can you clarify what you mean when you say that their history was totally cleared? Should fatemeh_baghdadi5 have various topics and replies listed under the activity section of their profile?
If that is the case, are those posts now associated with the fatemeh74 account? They should exist somewhere on the site and be associated with a specific user. From an anonymous user perspective, I’m not able to find a user with the username fatemeh74 on your site.
There is a background job called EnsureDbConsistency that runs every 12 hours. It might be interesting to either trigger it manually from sidekiq, or wait and see if everything gets fixed automatically in the next 12 hours.
If you do end up having two accounts that should be one, you should be able to merge them. I would definitely take a backup before attempting that, however.
It’s really hard to understand what’s going on without having direct access to everything, but hopefully we can get it figured out!