Highmark Blue Shield

I went to my support group meeting tonight only to find out that Highmark blue Shield sent out a letter to my doctor on September 23rd stating that the critera for weightloss surgery will change on November10th. The letter is vague and ambiguous. Now you must have a 6 month physician supervised diet and exercise program. You must document a supervied low calorie diet admiinstered by a dietician in your past. How can they arbitrarily just do this? Two other people at work have had this surgery this year and did not have to meet this critera. I am very upset. Any advise or comments would be most welcome. How do I fight this???