After our auto accident in 2008, the emergency physicians group billed us for the remaining amount after our insurance agency paid the reasonable and customary charges. I sent the bill onto our insurance agency and they sent a letter to the physicians group stating that any disputes regarding unpaid balances were the responsibility of the insurance company and not the insured (my husband and I) and to send all further inquiries to them. Nothing was heard after that by either us or our insurance agency. Three months ago, when inquiring about refinancing our house, we discovered that they physicians group had sent the bill to collections and both my husband and I have an unpaid collections balance on our credit reports. No letters were sent to us letting us know they were sending it to collections, nor to MetLife (our insurance company). I called the physicians group and have been stonewalled with no answers except to be threated with legal actions. Is what they did legal?

Maybe. They may or may not be bound by the terms of the insurance coverage. If they did not agree to accept R&C then they may not have been under any obligation to deal only with the insurer.

However, they were required to properly inform you of their collections efforts.

When you receive medical treatment, you are liable for the payment, not anyone else. Often insurance agrees to pay, but I will assume your medical insurance paid, and you would be liable to pay the difference, if the car insurance under med pay they were to pay the full amount if the doctor did not agree.

When you go to the doctor, there is an agreed to price often between doctor ( or hospital) and the insurance company, but a they are not required to accept what the insurance company says is "reasonable ** unless it is a medicare insurance** or unless they have a contract that requires them to accept the reasonable amount.

So no they don't have to bill anyone other than you, and when you did not follow up, they considered you refusing to pay balance.

OP is using the terms "insurance company" and "insurance agency" interchangeably. They are, in fact, two different entities. In some States Physicians MUST accept what no-fault pays; in others, they do not. I don't even know if OP is in a no-fault State.

Having a collections matter on your credit report is NOT the same thing as having a Judgment. There is no requirement to notify anyone that a matter is in collection, has gone to collection. Judgment, yes. Collection, no. Apparently the Physicians sent bills, OP forwarded them (to company or agency, I'm not sure), there was no follow up. OP can always file an explanation with the reporting agency BUT an unpaid bill is just that - unpaid. The Physicians care little who pays them, just that they are paid.

If Metlife refused to pay, I'd find out why. And the responsibility of the other driver involved?