What is the point of this Medical Aid?

I recently had blood work done at a doctor. I have just received a bill from the Laboratory that I am due to pay R1981.80 as Momentum only paid R808.50 of the total bill of R2790.30. That is only 29% of the bill. When querying this with Momentum, I am simple told that the Lab charges are higher than the agreed rate and all other items are not covered. Keep in mind I have done these tests more than once and have never had an issue. I am constantly disappointed with Momentum - I do not know what I pay for, as I seem to pay cash for more than 90% of most expenses. I am also constantly told I have no funds, yet when i query this I am told that is not true and the reason why they do not pay for any medication is because it is not formulary medication - even when I have received the generic versions. This has really the last straw, and has left me extremely unhappy and I am considering cancelling with momentum and moving to another medical aid as soon as possible.