Dude, there's always gonna be trolls. Most people join servers just to get staff; and if they don't then they threaten you that they will ddos, hack etc. My advice is; don't worry about it, most poeple who ddos only send like 30 mbs which is like 2 people joining the server. Hacking on the other hand, its not possible unless you've been practicing for 10-15+ years. And that hit that you have on your server, well doesn't matter really. There's no point for people to join your server and troll. It's like someone trying to hire bill gates and tell him that he won't pay him to murder you. There's no point for other people to do so. So my advice : screw them, just act as though they were never there in the first place.