Netcare Rosebank billing nightmare

As per any medical procedure i obtained pre authorisation from my medical aid. I was admitted to Rosebank hospital to undergo reconstructive knee surgery. After the surgery i received a number of invoices ranging from hospitalisation to even from the anaesthesiologist. Phoned my medical aid questioning the invoice, medical aid asked me if it was an in or out of hospital procedure. I corrected them saying it was in-hospital and had pre authorisation for the operation. I also received an invoice from Rosebank netcare stating that my medical aid limits was reached and i am liable for the invoice, i contacted my medical aid again with regards to this, they notified me that the operation was booked under a non severe day case and that the Hospital should change it as i am 100% covered for in hospital procedures. I notified the accounts department about the instructions i received from my medical aid, the accounts representative said she will take it up with the case mandager and resolve the matter. A year has gone by without any communication from Rosebank netcare or any response to my previous e-mails. Now they are handing me over! This is unacceptable!!