My son was physically bullied last year being choked, pushed and punched.  The principal would not help because he said no one saw anything.  No one saw!? this went on for about four months.  Finally, I phoned the school board, PTA and superintendent (thank god for her) who finally listened to me, and took care of this.

Moral of the story... Keep talking, keep telling.  Keep finding someone who will listen!

Do NOT stop until you get results! Tell the media, your PTA, school board, and everyone until the bullying stops!