Not sure where to go

I’m not at all sure where it who to turn to about this. I’ve talked anonymously to the Greek Affairs office and there is little they can do. Maybe publicly embarrassing this person may help? There is a sigma chi that sends out fake text messages and makes them sound very real. He acts like he is an officer in the fraternity and harasses seniors in high school. He then screen shots the conversation and shares with not only sigma chi but other fraternities. He is a mean low life. I can’t believe sigma chi, who has some of the best guys and future leaders in their group, would extend a bid to someone of this caliber. Not going to mention names but if you know, then you are implicated too. Pretending to be an officer should get a person kicked out, right? Especially if it was to frame and embarrass someone publicly. Tell me what to do. It’s one of my good friends that he did this to and he has moved on. I just see this sigma chi continually harassing unknowing people while representing sigma chi. That is just wrong!