Refuse to pay for blood pressure medicine (vital med)

I hereby request urgent answers from Discovery Health medical aid. They do not want to pay life-threatening medicine. The doctor described Irbewin 300 for blood pressure. They insist me to use generic medicine (that is cheaper). I tried various generic medicine several times but had very bad side effect from the generic medicine and had to sop and throw it away. (It cost me money every time, and it is not cheap medicine). The surcharge for Irbewin is huge and just a small portion gets paid by Discovery. They just say I must make use of the generic tablets. My doctor had to send a letter to Dischem asking them to never replace the Irbewin 300 as the side effects of all the others we tried made me very sick. I can't use cheap medicine that makes me sick. I pay my medical aid premium every month, and they can go back into my history since 1980, I luckily am quite healthy and was in hospital around 3 or 4 times in 30 years, still they do not want to pay life-threatening medicine. I also started using a half (150mg) of the prescribed which upset my doctor, but what can I do? If I stop using this medicine, I can end up in a stroke which will cost the medical aid much more that this medicine. The pharmacies maybe must stop paying commission to the doctors and make the medicine more affordable. Sleeping pills, that people use to commit suicide, cost R30 for 10 pills, but blood pressure medicine that is needed to prevent heart attracts and strokes, is unaffordable, as if the medical aids want us to get serious ill so that we have to use more medical aid? It seems they are only interested in taking our money without assistance of their goal, to assist members in their health. They chase profits to benefit the management at the cost of patients. I want to understand why they insist that I use generic if it does not work with me. What do they think of me? To have an unfulfilled life with bad health? In the meantime, the premiums get higher each year. What do they think what their purpose is? Do they KNOW what the purpose of medical aid is?

Your assistance to help me will be appreciated.