It does sound unfair but unless you can appeal the previous decision and use the example of the other student I'm not sure it's healthy to focus on that. If there is a civil rights group on campus or anywhere close by I think you should speak to them and get an opinion on any possible legal recourse.
And no I don't think there is anything you did wrong and this is not your fault in any way. I hope you don't mind but I have to say that I admire you for hanging in there and accomplishing so much under so much duress.