Ask HN: What to do about my erronious medical bill?

A year ago my wife an I went for our annual physical. It should have been free under our insurance. Mine was, but she got a bill for $214. I have called, written, emailed repeatedly both my insurance and the clinic. This is the story each tells me.

Insurance: "We only charge because of how it was billed. You'll have to get the clinic to change the billing codes"

Clinic: We don't guarantee anything will be covered. Call your insurgence.

I've looked at the codes. They are the same. With this information I was finally able to get someone on the phone with the insurance company who knew what he was talking about. It went something like this:

"Hi this is Ted how can I help you?"

"The same codes were used for my wife and me, how come she is billed an I am not?"

"Hold on let me get my boss"

"Hi this is Tom how can I help you?"

"The same codes were used for my wife and for me. Why is she getting billed and I am not?"

"hold on let me get my boss"

"Hi this is Mike how can I help you"

"The same codes were used for my wife and for me. Why is she getting billed and I am not?"

"Let me look"

"Oh, she was billed as diagnostic, and you were billed as preventative. You'll have to get the clinic to change that"

So I call the clinic and they say of course, they will resubmit right away

Now, A month later, I get a note saying the bill is being sent to collections.

So here is the deal: Insurance refuses to do anything. The clinic always says they will take care of it but never does. From what I can tell the fault is with the clinic.

How can I make them do something. Is there some sort of formal notice I can send? Should I get a lawyer? What kind of lawyer?

Should I ask this question on some other forum? or Reddit maybe? Help my out gentlemen.