Got an allergy and breathing test in Feb 2015 which was fully covered. In March 2017 Aetna "changed their mind" and decided I was no longer covered for the two year old procedures. Received a $900 bill in the mail that is now in collections. Everything I see online shows a fair market rate price for what was done at about $300.

I filed an appeal with Aetna, which they promptly denied. I've also filed a claim with the WA State Insurance Commissioner but haven't heard back (it's been a month). The hospital claims they have no appeal process even though Aetna said the rates are "negotiated rates" between the hospital and Aetna.

What's my best course of action? Keep fighting, or hope I can pay the collections agency way less than what they're asking?

Edit: Just got a response from Aetna through the State a few minutes ago saying they will not lower the rates. "Although the rate listed on the EOB was greater than the market rates referenced, the facility is contracted to provide the services rendered at a higher rate." So basically this is saying "we know these charges are high but we can do whatever we want."