Health insurance/Covered CA question

I have a weird issue with my health care provider that I can’t seem to find a solution for. I was pregnant in 2021 and delivered in February 2022. I had high deductible insurance in 2021 and switched to another high deductible insurance in 2022 due to change of employer. My job separation wasn’t until end of 2021 and my old company may have given me a grace period on insurance – my old 2021 insurance was in effect until Jan 14, 2022 while my new insurance was effective as of January 1, 2022.

OB care and labs in 2021 were billed to old insurance.Most care and delivery in 2022 were billed to new insurance, and my high deductible is met for the year.

I got a $2k bill for CTP 59426 ANTEPARTUM CARE ONLY on 1/3/22 that the provider billed to my old insurance, and since the old insurance was still active they’ve accepted and adjusted it, but I owe most of it due to high deductible (and it’s the only 2022 calendar year bill to hit the old insurance).

I’ve asked the provider couple times to bill it to new insurance and every time they say OK and then send me another bill for balance. Finally, called again, asked to speak to supervisor and the story is that every time they submit the request, the billing/insurance department kicks it back because it’s “global billing” and “I put a deposit towards the services” and “they can’t change the insurance”, even though obviously they can and did for anything past this bill. I can’t speak to the insurance people directly, the supervisor I’m speaking with isn’t really understanding the explanation either, just repeating what she’s told.

I’m trying to figure out what my options are. I don’t want to be stuck with a $2000 bill while my current insurance should cover most of it, and I’m not sure what recourse I have.

Edit: one of the “suggestions” I was given is to call my old employer and have them change the end of insurance retroactively (assuming they can actually do it) to 12/31/21, which then would potentially have old insurance deny the claim and cause a rebill on the provider side. Dealing with some of the insurance bureaucracy in the past, I can’t fathom how stupid the outcome of this could be.