LPT: If your doctor firmly believes that you require X treatment/medication/etc. Have them use the specific term "medically necessary". If your insurer kicks it back with that phrasing attached, contact them. Ask for the medical license number of the doctor who indicated that it was not medically necessary. Push for this information (they won't have it) and continue the line of "Someone on your end is making a medical decision against my doctors orders. I require their credentials so I can confirm they are a) qualified to make medical decisions, and b) have a higher education that my doctor possesses."
Things got weird when we went digital.