GEMS not paying medical bills claims.

I am unhappy with my medical aid scheme (GEMS) in 2022 I went to theatre for a procedure and its has only come to my attention that GEMS did not authorize/pay the full claim for an anesthetic of which I now owe them +- R2000 for anesthetic. Last year I visited the doctor and also the claim did not go through and I now owe the GP R600 for that claim. Its really unfair to know that we paying for the medical aid every month to cover our medical bills but they are failing to pay full claim to our doctors.