Electricity bill being hiked four times the amount

I have been staying in a two bedroom flat in which Quest Meters supplies electricity from October 2014 paying for electricity between R600 to R700 per month until june 2015. Then from 04 july 2015 my electricity bill was R992, 04 August 2015 = R1310.22 and 02 September 2015 = R1194.54 and now my Final statement 30 September 2015 = 4196.26, I have now moved out of the flat. All of this is happening while I have not bought any new electrical equipment nothing has changed in terms of the number of people. When you call their call center, its their agents were taught in school in how to be rude as quote on my last call when I questioned the bill this is what was said to me \ You can come to our offices but that won't change anything"People never ever trust this Company with their billing """