Ultimate Facebook and SPAM issue

Hi,

I am using WP 3.3.1. and BuddyPress 1.5.3.1 and Ultimate Facebook 1.6.2

Since 3 days I have many fake register users. CAPTCHA is active and WordPress sign in widget is not active.

So the only way to register is to use Ultimate Facebook.

Each day I have to delete them manually...

How can I handle that ?

Thanks

Lamine