Confused about authorization / medical necessity – am I at risk of being stuck with a massive bill?

Rough timeline of events:

Saw a new Gastroenterologist after moving to a new state. I explained my history with tests and procedures to investigate chronic issues, and he determined best course was for me to have an endoscopy. The last one I had was last year.

Had the procedure scheduled. A few days before I was supposed to arrive, they called to tell me there was an issue with my insurance – they said the location my procedure was scheduled at wasn’t in network. I re-scheduled for another facility and was not willing to pursue it without that settled.

Days before the rescheduled procedure, I called to make sure everything was in order with insurance, and to ask about my prep because they never told me what I needed to do, or what address I’d been scheduled for, and I never received a confirmation of my new appointment time.

[Hindsight is 20/20, and at this point, keenly aware of their incompetence – I should’ve asked for proof of authorization…]

Anyway, during that conversation with the office, I specifically questioned multiple times if insurance had cleared and they dismissively cut me off “you’re fine”.

I show up and have the procedure, to my knowledge and the best of my recollection – no papers were signed that indicated the procedure wasn’t authorized.

Fast forward weeks after the procedure… I get a letter from Cigna that says the procedure was deemed not medically necessary. I completely panicked. The letter says nothing will be paid for… I’m absolutely terrified. I called Cigna and hold back tears to stumble through the whole saga – and essentially what they tell me is that the doctor was denied authorization for this procedure, and that the Dr. never responded to requests for supporting information.

In an interesting turn of events – my follow up appt to review biopsies was supposed to be last Monday. They called again the day before my procedure and left me a message that there was a problem with my insurance. I called back and to no one’s surprise this office is nearly impossible to get in contact with… finally they tell me they’re cancelling my appointment because my doctor no longer accepts my insurance. End of story. No solution provided. I was floored – like can you guys email me the results? “Not sure”. Is there some other provider that accepts Cigna that can review my results? “maybe”. It takes them forever to agree to schedule me with another doctor to review results. Interestingly enough, during that follow up with the new Dr. she tells me that my Dr. should be able to perform my follow up procedure because the insurance thing is a temporary issue?? When I talked to Cigna today they told me his contract with them doesn’t expire until July 1 – so it’s very strange to me they cancelled my follow up with him at the last minute while he’s technically still in network.

The main thing I’m concerned about at this point is my liability in this situation for the procedure I had (surgery under anesthesia), and what I should do to protect myself financially. I obviously had no idea they didn’t successfully get the procedure authorized with my Insurance. I have claims filed for the biopsies performed, but they have not filed any claim for this procedure. What is my best course of action? Cigna told me they can’t make me pay if they didn’t get it authorized – is this true? Should I lay low hoping that in their utter incompetence they let 90 days pass without filing any claim? Could they still bill me?