Most of my experience when it comes to bullying has been petty and nowhere near as intense as your experiences, so I can't imagine what you're going through. I'm genuinely angered that teachers, specifically, can be so rotten. Our jobs are not to punish, but to protect. Regardless of whether or not you believe the student is in the wrong, if someone approaches you with an issue [i]multiple[/i] times, with physical evidence, it's our job to take action.

Perhaps we do it differently stateside, but next to the issue of bullying itself, the treatment you've received from people who are meant to promote the wellbeing of the student is total shit. 

For what it's worth, I'm sorry you have ended up with the short end of the stick. But the fact that you're around, and vulnerable enough to share you experience is really admirable. I don't know what else I can add that hasn't already been mentioned, aside from maintaining that hope for the end of school and to no longer see those kids again. :(