Ahh, there you are. I've been mulling over leaving a tag to warn the community, and the only thing that stopped me from it was the lack of OP's update, that made me assume the situation has been clarified.

Regarding no username, yes, that's his issue. He suddenly found his username to be invalid, and when he tried to recover it, they got an error message saying that the username was not found.

Can you check user's account with their email address? Or other information that you can match with your database to get a better insight of what happened with account in question?