Pre-authorization denied for service already performed.

So I have a situation (maybe) where I am not sure what my next steps are. I am an adult congenital heart patient suffering from heart failure, and I recently went into the emergency room with chest pain and shortness of breath. After a few hours in the ER they told me things looked ok, but based on my cardiac history they wanted to hold my meds for a while and admit me to the hospital so they could run more tests and observe me. After two days in the hospital they sent me home.

I noticed today that on my insurer’s website portal my insurer has denied the “pre-authorization” for the inpatient hospital charges (which I guess are different than the doctor’s charges?). I’m not entirely sure what is going on. I’m not sure what a pre authorization is for services that were already performed, but I am not sure if this is going to be an issue or even who to follow up with. According to the denial letter they said the reason for visit was “chest pain”, which alone is not enough for inpatient care without other symptoms, even though I had other symptoms.

I also noticed a line on the denial letter that reads,

“Member billing by participating (in-network) providers (doctor or facility): If your care by a participating provider is denied based on medical necessity, the provider is not allowed to bill you for the denied services unless you knew in advance that the services would not be covered and you agreed in writing to pay for them. “

The only consent I gave was verbal consent when I first entered the ER, and this was hours before they had made the decision to admit me. Though I know hospitals are sneaky in their language.

Curiously the tests and treatments they performed while I was admitted are being covered. This seems to be the hospital charge for the observation.

The hospital is in-network and is a big city hospital, and I am not even sure where to go next with this.