they guess their readings and overcharge/over bill

It's with deepest frustration that I'd made a query & I've still not received help- The only response I got was that I consume a lot of electricity during winter-which's not true.How come my electricity consumption gets more expensive every month (winter/not) & yet during the day there is no one at home. How can a house of one adult & 2 kids who are all not at home during the day consume electricity of almost R7000 for a single month? This's really upsetting and now I don't even know what to do or who to turn to because it seems as if my queries/complaints fall on deaf ears. I don't even have a meter, so how are these readings compiled?Winter or not, there's no way whatsoever considering these facts, 1.the size of my house. 2. Using gas heater,3.Not cooking every day, 4. Considering load shedding (during winter-where they claim I consume a lot of electricity), 5. I do not cook every day & 6. Switching off geyser- I'd use this much electricity in 1 month. statements dated 2015/09/15 for electricity's R6864.18(reading dates 15/8/14-winter was over-they guessed),2015/8/4 it,s R3267.34(r/d 15/07/13-above points),2015/7/9 its R849.22(r/d are 15/6/15 and yet it is far less than the above