Authorisation approval that was a lie

I have been a member for numerous years, last 2023 I had problems with my right knee and the Dr gave me treatment and suggested that if the problem percists I will be required to do an Arthroscopy. Then last year in December on way to work I fell and injured my left ACL and the Dr suggested that a surgery for both knees must be conducted authorization was obtained for both but they paid for one. I am left with a hospital bill of 28000 when I call in to enquire I am being sent from one person to the next. I have sent numerous messages and they keep on telling me that they will look into the matter but still there is not even one call from them. I am very upset and I don't think I will continue with medshield