not sure of surgery date now

Hi,Today I was told that I may not be having surgery on Dec. 26. My Medicare plan has not approved my surgery yet, it's been six weeks, no reply yet. My doctor keeps giving me dates just in case I get approved. I've call Medicare they said that I am covered if I meet the condition required.The insurance lady at the Doctor's office said that the region that we are in they are slow about approval, that sucks.. So now I don't know when I'll or if I'll be sleeved. I'm so down now. My new life is in Medicare's hand. Is there anything I can do?.