Workman's Comp Has Stopped My Prescription For Fentynal 50mg. My

Workman's comp has stopped my prescription for fentynal 50mg. My back Dr does not agree but they will not agree to refill my prescription. I'm on medicare and it's very expensive. Is there another med that will help with back pain like fentynal does? I also take 3 or 4 oxicodon a day but only 1/2 at a time or I itch and have to take benadryl. I've been on these meds for 11years. I've had to cut my patches in 1/2 just to get by until I find a solution. I'm not completely out of pain on these meds but I can function, I've lowered myself from 100 me to 50mg in 2 year with my doctors help.