Prepaid meter it's a ***** n making the poor poorer mxm

In a single month city power have taken half my electricity units in the name surge ,if u buy R300 I get 45 kWh n if I buy R100 I get 15kwh n city power takes R50 dependung of the amount of power I buy they take half so I get to share my units money with city power every time I buy electricity,I'm not happy at all,just this month I have spent over a lR1000 rand's n I still get charged the surge that I dnt understand.