Hiden charges that make no sense

There’s hidden charges between the 1 and 5th of every month that we are not aware of and that don’t make sense . E.g when you buy electricity for R150 on any other day you get 39.0 unit but when you buy between 1st and 5th of every month the units you get are 16.0 must take into consideration the charges are already charged when you buy electricity but between those days it’s like they are doubled and there’s never a clear explanation as to why the difference. This means that cause you must pay for water the charges for water could be 159 and somehow you will end up paying 400 with little to no electricity unit and when you enquire you never get a clear understanding of where the extra charges come from and the fact that you can’t pay for electricity without having to pay for water and vice versa makes.