Health Insurance Woes

Okay, I've been in this epic battle with my doctor's office about a $200 bill that they never submitted to my insurance agency. They say they did, and never got reimbursed for it. I told them to resubmit, and they won't. I'm not gonna pay it because it's totally covered according to my insurance agency. So now it's gone to a commercial collection agency. What the hell?? He's in my insurance plan, and I only visit once a year for my RLS. I have no idea what happened, or why they didn't get paid...but for them to do this to me is insane. If he wasn't the best when it came to RLS, I'd find another doctor because of this. Seriously.