I'm at my whit's (sp?) end!!!

I have a 6th grader, who doesn't do homework , or even care about whether he's done it or not. I ask, do you have homework?? "nope" is what I get... then I find out in 4 of his 6 classes, he has an "I" they grade A,B,C,I Funny how you can never have homework, and you're almost a straight "I" student. He doesn't even hang out with kids that get I's he hangs out with A & B students, they go to reward events and dances, he doesn't , I don't get it, I do whatever it seems like I can, but obviously it's not enough, I realize they are trying to teach "responsibility" but with him, it's not working... I need advice I can take away every privilege and he'd be happy to just sit in a corner and stare at a piece of dust.... I email a teacher... no response... I really hate middle school.... I really hope he doesn't. HELP!!!