How do I stop spammers in my paid forum?
 

I have a forum that anyone can register for, but you must pay before you are given access. Every day I have dozens of spammers sign up, but of course, they have no access without payment. It is quite tedious to remove all these by hand. Is there a better way? Is there a program or add-on to deal with this?

I searched the forum and found one add-on that seemed like it might work, but I couldn't get it to install correctly. I'm by no means a computer programmer, so maybe thats the problem! Any help would be appreciated.