I noticed your question on e107help, but I am not sure if I know answer. Do you know Nofify system in version 2?
I ask just not to answer obviously thing.
I saw old banhelper plugin. But most of it's features is inbuilt in system now. What is missing is possibility to do this via frontend not only via admin area. But this would need to change your theme template to accept extending by other plugin. It would help if you write functionality by functionality you are missing..
Oh. And important thing - this notify system - I tested sending email if new topic is here, it works from admin. But not in reality. So I created issue. So maybe there is solution for you, it's just doesn't work as it should be. But user signup, banning for flooding work.