Diabetics and the pump?

I have a insulin pump and medicare has paid for the supplies for the last five years now they are coming back and saying I didn't qualify and will have to pay for them. I have had the pump for about 10 years and my insurance paid for it. There is a blood test to see if you are producing insulin but I need to know name and if you need to remove the pump before taking it. I took the test and was told not to eat but I didn't remove the pump. the cost is 586.00 every 3 months. i have tried calling my doctor but he is out for the week and this is running my blood pressure up. every place i have tried to get an answer I am told to leave a message or call back. They want me to pay for last five years of supplies.