Medical Claim "Under Review", how long do they have?

TLDR- How long can a claim be “under review” with no response from the provider?

I have been dealing with issues from my Gyn office since I started seeing them. I will try to break things down the best I can, to try and make giving an answer easier.

6/30 – First visit for yearly pap, should have been $25 (issues came up so didn’t count as free visit), they made me pay $50 up front. 7/13 – Ultrasound. They made me pay $150 upfront, with a notice at the bottom of the paper I signed that they would refund if insurance covered after 30 days. This also ended up being a visit that should have only cost $25.

7/27 – Colposcopy, hysteroscopy, and cervical biopsy scheduled in office. Had to pay $500 upfront(my deductible). During the appointment they were only able to complete the hysteroscopy as my cervix was bleeding so much that the dr was uncomfortable continuing outside of a hospital setting. This visit is still listed as “under review”.

8/14 – Pre-op. Had to pay $1000 upfront, they claimed that they contacted my insurance company and were told that this amount was my 20% that I would owe. However, they delayed in submitting to insurance, hospital claim was processed first so according to insurance I only owed $350 due to hitting my $3000 out of pocket max for the year.

8/15 – Surgery day. Had Hysteroscopy, cervical biopsy and polypectomy. Have received $1800 hospital bill, $250 anesthesiologist bill and $40 pathology bill.

As of today, 10/02, I have received $0 back from gyn office for overpayments. They absolutely refuse to answer the phone anytime my insurance calls them. My insurance says they are waiting for additional documentation from the gyn office for the 7/27 visit before they can process it. When I ask for updates they tell me they’ve pushed it to the provider outreach team and that I should check back in a week. This has happened 3 times now.

I can’t see the date that they submitted the claim website gives me an error I when I try to look at claim details), but its been 67 days since the appointment itself. I am waiting on this claim to process so that I can go to them with all my EOBs to get my total refund and not have to deal with them again. And the money that they owe me I need to pay the money I actually owe. What happens if they never respond? Is there a legal timeframe before they are SOL on anything and owe me a full refund for that date?