Operation not part of her medical plan

Okay, so about 7 years ago my granny died in a private hospital and the care she got till the end was amazing, I then forced my mother ( been looking after her for the last 10 years) who didn't have medical aid at the time to get medical aid,cant let her go to government hospital. We got medical aid at Bonitas, the plan that shes on (BONCAP) is all that she can afford( her government pension goes straight to the medical aid). Shes been complaining about pain in her leg for more than a year now and every time she goes to the doctor and complaints about the pain they just give her pain ****ers and then she still needs to pay in just to get the medication. We took her to another doctor and he confirmed that the pain shes having is due to a hip that needs to be replaced. 2 doctors have given the medical aid motivation letters to say that the hip needs to be replaced but Bonitas say no sorry its not part of her plan, so guess she will have to live on a bed now till the day she dies. Thanks Bonitas