You aren't banned. The server simply doesn't allow any kind of NetLimiter since people can use it to abuse, like to lag themselves.
If killing the process in task manager didn't work (it means that are still some parts of it that might be running and interfering with MTA), then just uninstall it.
I assume it should be located in C:\Windows\LTSvc or just use the Control Panel to uninstall, then restart your computer.