Please help regarding my son who was suspended for stealing?

I have been fighting my sons suspension for over a week. He was threatened to steal a bike for another student and if he didn't he would be hurt. The principal never gave him a chance to tell his story and when I called her she said she did not believe my son. he was lying to try to get out of a punishment. I just found out that the same kid who threatened my son also stol an Ipod touch the day before. My son had no interest in the bike it off ground by the other kid. My son has never been ion trouble and I can honestly say I believe him. The principal did admit that my son should of not been suspended for Robbery and extortion but for theft. Please help. And for those of you who are going to blame me and say I need to teach my son right from wrong I would tell you just wait till your child does something out of fear. Please help!