Bad Service at Pre-Authorisations

Today my husband was booked for a minor op on his injured left thumb. The specialist had to cut off excess tissue that had developed because of the injury(knife cut) that happened almost 3 weeks ago. The injury was not healing. We phoned discovery for an authorization number to do the procedure,1st they told the doctor's assistant they don't pay for the procedure, then I called to find out why, I spoke to Yolandi and she said they DO cover the procedure (both codes given by doctor) and she gave us the authorization code. We took it to the hospital (Mulbarton), when the hospital called Divovery to confirm the code we were kept on the line for over 20 mins until we hung up coz we already had authorization only to be called by Discovery again this evening AFTER THE PROCEDURE telling me that they are taking away that authorisation that I was given,it's no longer going to be valid because the procedure was not supposed to be authorized. I'm so angry I wish I could switch medical aids for this run around that discovery gave us! I spent soo much time on the phone with them while they were not even sure of their own jobs! How do you approve &disapprove a the same procedure at the same day?