Problems with coverage of important prosthetic part

I have been a left below-knee amputee for six and a half years. I have extra skin on the underside of my residual limb, which has caused multiple problems with fits on all of my various prostheses. The last several suction prostheses would not keep suction because of this. My current prosthetist did research on different systems and found out that the elevated vacuum system would be much better for the extra skin. It is working extremely well and maintaining good suction and vacuum. It is helping me get around better. However, United Healthcare Medicare Advantage has rejected paying for the vacuum pump, saying that there isn’t enough proof that it is any better for the health of the leg than any other system. It is $3,080 and I can’t pay for it on top of everything else. We are appealing their decision along with my doctor, but an insurance company should not be the final decision-maker on a vital part for a prosthesis when they don’t understand the health and welfare issues involved that a doctor and prosthetist have been trying to solve. This new system will be very important to me as I walk, exercise, travel for my job and participate more fully in my life.