Worst experience with Discovery

I am in Discovery Classic smart plan. My wife had fracture in Septemeber and then had surgery in waterfall hospital which is under smart network. I received notification saying that they will only pay 87% of the the total cost. The reason was not mentioned and then I called the customer care twice. First time, the agent said Waterfall is not day surgery hospital and we should have done it in day surgery hospital. I dont know how Discovery will decide how long the surgery should take. Spoke with the doctor and he gave motivation letter. So I tried to call center again to ask where to send the motivation letter. Now this guy said they are not paying because there is a miscommunication between doctors room and the discovery so they will fine the customer. How the patient will know about the surgery details. This is very ridiculous behaviour of Discovery healthcare. I asked him to send me email about what he said, but he sent same letter twice which I received initially and it doesnt have any info about why they didnt pay full amount. This is clear robbing the loyal customers.