It's an anti cheat plugin installed on the server to reduce the number of people using hacks such as aimbots, no-recoil and wallhacks. If you have been banned by it, chances are you were aimbotting, wallhacking or had no-recoil on. It's very good at detecting these hacks, so your best bet is to make a ban protest in the Ban Protest section with your ingame name, Steam ID and explanation.