I´m looking for an option where only members and of course the administrator can see the usernames.
Some members register with their email address or even full name so it turned out to be easy for non paying members to find the users on facebook. Since the username can not be changed the only option is the delete the profile and create a new user.
I have seen following topic which describes how to hide the username from the profiles.
however thats not what I want. I as the administrador still need to see the usernames.
https://archived.seventhqueen.com/forums/topic/hide-usernames-display-only-real-names