Hospital and insurance disagree if hospital is in network, leave me on the hook. How do I get them to talk at a higher level?

Last year I had two health events. I was hospitalized in the Spring and then had surgery in the Fall. Both were at the same out of network hospital (I checked, and it is the same legal entity).

My insurance has a 50% out of network co-insurance, and an out of pocket maximum for OON charges. My hospital stay got billed according to this.

However for my surgery, my insurance company says that the hospital is in network. They paid a small amount, and then list a huge negotiated discount on my Explanation of Benefits.

The hospital says they are not in network and do not accept the negotiated discount. They say I’m responsible for the huge amount insurance won’t pay.

I’ve contacted the hospital, but they just say it’s my problem and I owe them the money. They don’t care about my insurance, and say that’s my problem to deal with.

I’ve contacted my insurance twice. Both times they said “oh this is a little mixup”, and the person put me on hold while they faxed another copy of the EOB to the hospital. Then they come back on the line, tell me everything is fine, and hang up. But this doesn’t change anything! When I talk to the hospital a few days later, they just say they’re rejecting the discount again.

At the moment, to be clear, insurance has not paid anything close to what my policy states for an out of network claim. It’s supposed to be at least 50%, and it’s closer to 10%. I’m freaking out, seemingly caught in some Kafka shit.

How do I get the insurance company and the hospital to talk about this?