disability insurance through liberty mutual

i'm not sure if this is the right forum, but i need some help, please.

i had the roux en y on august 5th and have been out of work.  i just found out that my disability claim has been denied because the surgery was not seen as "medically necessary." per a review of my doctor's records by the liberty mutual doctors.  i've been paying the premium for this insurance and i *really* need the payment to make ends meet until i'm getting my regular paychecks. 

i do not have diabetes, sleep apnea or hypertension.  but i did have a bmi around 50; i have pcos and insulin resistance/metabolic syndrome.  my weight was affecting my job, my health and my sanity.  my health insurance deemed it medically necessary, not elective.

has anyone here dealt with the appeals process or have any advice for me?  i need to fight this and win.  i'm going to try to get all my medical records from 2004 to present (when my health started to decline) to show proof of all the above mentioned conditions and write a letter to the insurance company.  i don't know what else to do.