I’m sorry to hear you had a bad experience. However, I do wish you would have submitted a support request before posting a negative review.
I put together a Troubleshooting Guide and FAQ’s for users to check when they have issues. There is also Support Request Form for you to contact us if those don’t work.
The plugin definitely works. The only time I have heard complaint like this is regarding registration spam, when users haven’t read the plugin documentation fully. It clearly states that it stops registration spam for the WordPress registration page only, not for third party plugins like BuddyPress, etc. I’m willing to bet that you’re using one of these.
Please re-read the documentation and consider updating this review.