They put my Child in special education for no good reason?

I believe that they are sending my child to special education for no good reason. Okay, about a week before they sent my son to special ed me and the principal got in an argument over his late home work (I told her that I accidentally threw it in thew trash and she told me I was just covering for my sons laziness) Anyways to make a long story short a week later I got a letter from the school saying that they was going to place my son in special education for: 1. Misconduct 2. Failure to keep up with the rest of the cl 3. I forgot. First of my son has never had problems misbehaving in school, in fact his third grade teacher complemented me on his behavior saying how he was the most well mannered student he has ever had. And with the grades I know my son isn't an A+ student but he has always made Bs and Cs. And suggestions on what to do? (Next school year)