WLS was covered last year but not this year

My insurance covered WLS last year but they do not cover it this year.  I was told that if I notified the insurance company (BCBS of IL) that I was doing all the leg work to get this surgery approved that they would cover the surgery.  I sent them a letter twice last year to tell them of this and sure enough they claim to have lost my letters.  When I spoke with my company they said for me to send a letter certified of everything that has happened along with copies of the letters I sent them and they would see what they could do to help me.  Does anyone else have any suggestions as to what I can do to help this matter??? Thanks, Chrissy

Chrissy  I have only one thought in this matter..and that is..Does your doctor have any documentation where you were pursuing the WLS? If so,maybe a copy of that documentation to your insurance company would help. hugs and good luck