Submitting an "External Appeal" for Medical Claim

Hello,

I have a medical claim for a surgical procedure I had in July 2022. I have been fighting my insurance company, Excellus Blue Cross Blue Shield for about 10 months now to get reimbursed for it. The process has been extremely frustrating and they have continually denied reimbursing me for the claim for one reason or another.

We have now reached a point where they issued me a final adverse determination letter. It says the last step I have is to file for an external review of the claim. I live in the state of New York and I believe the claim will be reviewed by a board of individuals that work for the state.

The medical claim is for $37K, so obviously I feel a lot is on the line and I would like for my external appeal to be approved and for them to override Excellus's ridiculous decision. This is a totally new process for me and I'd like to ask if anyone on here can shed some light on how this works and what I can do to ensure a favorable decision for myself.

In case some background would be helpful:

I had a chronic excessive facial blushing and sweating condition that started in my teen years. It was a debilitating problem socially and professionally. I had two surgical procedures done to control it. The second procedure left me with some severe side effects. I had a reversal procedure done in 2018 to try to improve the side effects but the reversal attempt was a failure. I then sought out a specialist to make another attempt at reversal. The specialist was in Taiwan and I traveled to Taiwan to get another reversal surgery attempt. Prior to this second reversal surgery, I called Excellus numerous times to verify coverage and they assured me it would be covered. However as soon as I submitted my claim after the surgery it has been nothing but games and nonsense from them. They are now saying the surgery wasn't medically necessary. Excellus did cover my first reversal attempt in 2018 and it makes no sense why they are suddenly denying this one since it is essentially the same exact procedure.