Ekurhuleni Munipality *******ion on Electricity

I would like to get help with the electricity tariffs they have placed in my bill. I bought electricity for R700 and i only got 150 units At first i thought it is a mistake they will rectify if but this is going on and on. If i spent R50 on electricity i get 11 units. So i went to Ekurhuleni Municipality and the guy whom i though will help simple told me to go and buy once off electricity to avoid buying in bits and pieces. i bought electricity for R1000 first week of the month and got 500 units.it did not last a month and buying extra units are spend a lot and less units.. I live in a low cost area called Phumula whereby most of residence have prepaid box. Since April I have complained about the tariffs but nothing has been done. I suspect that that somebody is benefiting from this, I went to check with my neighbors and they were all surprised about my ordeal. I am single parent and would like to get to the bottom of this please assist me as i live days without electricity