EOB says we don’t owe, dr office disagrees

Sorry it’s long!

I have a long term claim/eob issue that I’d like another perspective on. I will try and keep this as short as possible. This all takes place in Illinois.

Back in 2019, I started IVF treatment and we had infertility coverage through my husbands employer for a total of $30k. Before every treatment we received letter from Cigna approving treatment. In September we did the first egg retrieval (and received said approval) everything was fine, it seemed like everything was taken care of. At that point we had hit our OOP so we weren’t worried about bills Fast forward to 2022 we received a bill for $4200 from the office for that first retrieval from September of 2019. We spoke to office and they said it took the insurance this long to process claim and that we owe because we hit our lifetime max. This didn’t make sense to us since apparently everything else (other retrievals and meds) were paid for, all of which came after the date on that claim. We call Cigna and they determine that we do not owe that bill because the billing department accidentally billed it in my husbands name, not mine. We also were sent the EOB stating that and that our responsibility is $0. From then several things were said by the billing department. For one the guy claimed that that’s impossible since they don’t make mistakes. He also said that he called the insurance and that he was told that we passed our max. Last October he said that there will be a call with him and the third party insurance as well as Cigna, to figure this out. We didn’t hear anything for 6 months after this and thought this was it.

Then in June of 2023 we started getting bills again. Office emails us asking us to call the insurance and to tell them to “rectify their mistake” We call Cigna again, same thing- we don’t owe it. The EOB is very clear about this and we were well within our limit. A couple weeks later we decide to call again (possibly a mistake) to hopefully have them talk to each other. Mind you this was probably the 5th call to Cigna, where everyone said we don’t owe it. She was on our side, went to call the billing office and we were on hold. When she came back she changed her tune and said we do owe it. Her explanation was that while they did bill it wrong in 2019, they apparently resubmitted it correctly in 2022. (the initial rejection from Cigna was in late 2019, so it took them over 2 years.) by the time the resubmission happened we did hit our $30k lifetime coverage for ivf, which is why we owe it.

A couple questions-

isn’t there a timely filing? It took them two years from getting the initial rejection due to their mistake to fix the claim. Do we have any recourse in arguing that at the time of service we were fully covered and within limit?

can we just go by what the eob says and ignore the billing department? Except for the last time, everyone at Cigna has been on our side.

it’s been years, if they really had a case wouldn’t they have just sent us to collections by now?