Worst claim experience

After receiving my pre-authorisation (***5) in June 2020, my operation has cost me more than R20 000. Myself and the accounts department at the Doctors offices have struggled to get payment / feedback from GEMS from day 1... Now to top it all up, I receive emails from my Doctor and the anesthetist (whom I already paid my portion to) 4 months later informing me that I still owe money as GEMS has now reversed some of the payments - even though did not even pay a 3rd of the pre-authorised operation. How is this possible - My operation should have been paid in full. Why does a person contribute monthly for a medical aid if they DO NOT PAY! I am not the main member, so when I phone, they cannot help me or give me answers. I am also in the client servicing industry and this is by far the WORST experience I have ever had.