Telkom is *****ing my money

I'm very disappointed with telkom, I've been a loyal customers for year and reviewing my contract with them at all times but right now I'm so sick and tired of them taking money I don't understand comes from , I recently upgraded my contract , I took a contract that requires me to pay R99 , I get 500 MBs of data ,together with 5gig on monthly basis . I was so shocked when I received my bill that I owed R388 towards this contract. When I called the contact center I was told that they have added spending money on my account and they have been charging me based on that amount they have added, like that's just day light ******* , how can they choose to do that when I have so much data , they just wanna take money ... I'm so upset that even thinking of reporting you to icasa because clearly your sale consultants are selling wrong information... you used to be the best but lately you've been succeeding at just chasing off your customers , almost every customer that takes up a contract with you complain about the same thing... if you don't fix this carp I will sure be escalating this . I have another contract ending in just, I was considering to upgrade it but with all this **** happening I think it's best I move to your competitors