all I can say is documentation, documentation, documentation.....I am using my iunsurance as out of network, so they will only cover 80%, but NYU will actually accept 80% of usual and customary in my case. so I wont have to worry about the other 20 %.
just keep plugging, and be persistent. if you dont get the answer you want, ask for a supervisor...if they dont give you the answer you want, ask for their supervisor. you have to be pleasant, but stearn. write down all your conversations (I have an entire notebook!) and remember, the insurance companies have this liitle clasue thats recorded before each call that says basically no matter what they say, they basiucally can still change their mind. but be persistent and you should be fine. the hoops they make you jusmpthrough are basically so that you will give up...JUST DONT GIVE UP. even if you get denied, allow yourself 5 minutes to be upset, then get pissed, and keep going. if you really do medically need the surgery, you will get it approved.