Fedhealth approved procedure not paid in full

I had stomach pains so went for tests and was diagnosed with a umbilical hernia. My procedure was authorized for 22nd of june 2021. I had a co payment of R6800 which i made on admission. Surgery was done a prosthesis mesh was used. September 20th 2021 i received a call from the hospital stating i am have a balance of R4998 due by me because medical aid didn't pay for the prosthesis used. I contacted fedhealth and was told by the consultant that theres a mistake and i must not worried everything will be sorted out with the hospital. They will ask hospital to re submit the claim because it was an aproved procedure. 10th of November 2021 i received an email from netcare final demand of payment. Fedhealth says prosthesis limit exceeded and is going to change it to pmb or pms for payment. To date and time nothing has been done. This medical aid has to be the worst of my experiences.