Avoid email as username when connecting with Facebook

Hi,

I use the connect or subscribe Facebook utilities that is include with Easysocial. The problem is when people subscribe their username is their email by default. I have to check every hour and change the username for their security and the security of the site...

Is there a way to avoid this ? I have at least 15 new users per day...

Thank you for your help. I installed Easysocial and my members like it a lot. Better than Jomsocial

Lili