Appalling service, if you can even call it service

I cannot believe I have to go through this with this medical scheme again. in Jan I called Gems to ask for authorisation to get a Gastro scope done, 18 Jan I receive a letter saying that I have been authorised to get the procedure done on 31 January. I get the procedure done and all of a sudden I am getting calls from my done saying that the medical aid is refusing to pay. I called Gems and I am told that they decided to revoke the approval, no one communicated this to me and now I am owing doctors, I fail to see how its my problem that your employees are ****en *********** to add the cherry on top of the **** your consultants are rude, this lady had the nerve to make me hold and as soon as I asked to speak to her supervisor she went dead silent until I gave up and hung up the phone 21 minutes later. I wouldn't have gotten the procedure done if you did not send me the letter to say I have been approve, weeks later after the procedure was done you want to tell me that it was approved by mistake?? I need you to pay the doctors or refund me all my premiums back.