Obviously frustrating and shouldn’t be happening. If it was pre-authed, is it possibly a billing code mismatch? That may be correctable if you book an in-person appointment with the hospital’s financial office.
"shouldn't be happening" is a weird way to describe the behaviour of health insurance companies in the US that they engage in every day.
Why? I wanted to express sympathy for suffering in our system while offering practical advice. It seemed rude to just launch into advice without acknowledging it shouldn’t be necessary in the first place. What phrase would you have used?
Who do you book an appointment or call with if it's corruption and not a simple billing mistake in their favor?
You’d start with that office and escalate to the ombuds of both the hospital and the insurer, with your lawyer and the pre-authorization document and communication trail. I get your question is facetious but it’s still worth knowing how to navigate a broken system.