Spammers Wreaking My Forum
 

Well, we banned this one member of my forum for posting some inappropriate things. (We have a kids forum, many younger users come on it so we don't allow anything over PG.) We banned them, and they made there own little forum to try and trash us. Normally, we'd just ignore it. But, they constantly send spammers to come in on a few proxies (some that we can't block such as HideMy[butt]) and to spam us with things that are even more ban worthy.
I have reported their site to freeforums, as it's a branch of freeforums, but cannot think of anything else to do. Also, every time they come, we ban the IPs that they come in on. I'm trying to wait it out, and hope that they all get bored and quit. But, it's been going on for a few weeks now and they're still at it.
Has this ever happened to any of you and do any of you have any suggestions as to handle this problem?

Obviously, someone just got grumpy for being banned from your site. Just ignore them and keep banning them.

If it continues, find out their true IP and report them