Hope you get it straightened out, the same thing happened to me when I was about to turn 65. I turned 65 in October, signed up for Medicare and till the end of the year was still on my company insurance till 12/31. Fighting prostate cancer and was due a shot that cost $5500 in the middle of December. Medicare put in Advantage starting the same date as Medicare took over. My Urologist does take Advantage only a supplement, needless to say I didn't get my meds. My company insurance was secondary but not according to Medicare. Tooks me 5 months to finally get me on Blue Cross Blue Shield supplement. If you have any health problems I would stay from an Advantage Plan. In the Memphis Metro area there was very few doctors that accepted it. Go with the best supplement you can afford. Plan F is what I went with dealing with cancer and the side affects of radiation and hormone therapy. I may be wrong but was told you can always go down in plans but might get turned down going up.