Fedlies conartists

On the 22nd of Dec my grandmother fell and broke her bone on the arm,we immediately rushed her to hospital and a process to get her operated on began. Everything was authorized and approved by fedhealth and no one called to advise of any extra payments would be required. Operation went well and a month later the hospital calls to advise that there is a shortfall of R20906.05 that I am liable for. I call fedhealth who advise wrong codes were used and they would rectify, a month later the hospital calls again to say medical aid has still not paid and I am liable,I call fedhealth who than lie and say the hospital didn't request approval of procedure prior to operation. I get hospital documents to prove fedhealth are con artists who are lying about the whole process to avoid payment to hospital. How was I not made aware by fedhealth of all the extra costs why must I pay for their mistakes. This is my grandmother's first hospitalization since being on the medical aid in 2018 I am disappointed that a premium of R3100 per month has failed us on our first claim in 4 years.