Worst service provider

They decided to add "increase deposit" to my monthly bill, they couldn't give me the logic for the increase. Except that when I moved in the deposit was R900, now it should be R4000, so my bill went up from average R1500 to R5500. I made an arrangement to decide the R3100 over three months, which they agreed but then went ahead and cut my lights....I am working away from home, my children are in the dark as I write.....is there no alternative to these people??