electricity over estimated

i looked at my bill today and saw that i was charged R2842.28 for electricity as from (Jun-Sep) and i was fuming with anger because if its not water billing query its this.my water query has not been resolved still and i called the COJ call centre and the lady i spoke to said, because of old electricity meters readings being changed to new meters, the reading was estimated from June 2015. the funny part is. i was been paying my electricity which was over estimated all along. she even said i must still pay the bill for this month and they would credit me next month. of which i REFUSE to pay because they need to sort out their mess with my bill and send someone to check my water meter as well because i am still being overcharged charged.