I know for certain that OTM will ban players for abusive behavior. It has happened to a player on our server (not the one referenced by the OP). As the OP pointed out, hundreds of complaints have been made but appearantly they didn't rise to the level necessary for a ban.
Since this is actually a few people engaging in this behavior (yes, I have seen it go both ways), I suggest that you discuss this like mature adults and come to a resolution.
Akbar has already suggested this on page 1 and unfortunately this has been attempted numerous times in the past and does not go anywhere. This person goes out of her way to insult, demean, instigate, and torture many people on this server and frankly many are sick of it, hence why i posted this thread. We all understand the severity of this decision and unfortunately there is no other option that has not been attempted.