Cunc-
Please unblock these users. Blocking them just encourages the behavior. If I'm not mistaken, you have not been granted authority to block those usernames.
When Ed wrote "block", what he meant was "change the password". In this case, anyone could do that, so Ed did not need any special authority to do so. In fact, I will change the passwords of new accounts of this type myself if nobody else does. I have explained several times why these accounts are a bad idea and suggested alternatives, but the user who created them has ignored these suggestions.
Regards,
Erik