Billing dispute ? I had a routine, clean Colonoscopy. I recvd a bill, stated Dr was out of network. Not once was I told this the day of. Can I fight?

The procedure was a referral from Primary physician, I handed them my insurance card, and at that time, they should have informed me it was out of network. I would have never had the procedure if it wasn't covered fully. I received a bill stating Anesthesiologist was OON. They submitted the bill twice to Humana, they denied one because it was already submitted. Then we get a bill for Anesthesiologist for being out of network. We have been going back and forth on this for 2 months.Today Humana called and said it was definitely out of network. Primary physician said we were basically out of luck. Endoscopy physician office stated that they had just deleted Humana the day before my procedure and they submit some claims and not others??? That does not sound legal. Again, if I was not going to be covered, I WOULD NOT have had the procedure. What are my rights? Thank you