It is too old that I don't even remember the email address. Can you delete that? But I'd like to have the old username 'reversiblean' instead the current 'rev_siblean' without losing the current stats

Can admins do something?

We do not delete old accounts at this time.

I can only suggest using the forgot password feature and trying every email address you have ever had:

http://www.gametracker.com/account/forgot_password/