Apathetic service

Called CellC on 9th Feb to query additional R600 SmartData Internet fee on my account for the 1st time ever. They said i'd used this data & would get their technical division to confirm with me what i had used it on -websites etc.& get back to me within 24 or 48hrs, i forget exactly. Well, its now 02March!! I have received my next bill with the same additional billing! She said the data was validated !I have wifi at home, wifi at work, & for the 1st time ever have had the highest cellphone bill, twice in a row. When i called today & took the opportunity to express how unhappy we''ve been with Cell C from the outset - trying to get the billing right for the first few months, to poor signal, to poor customer service, even in store, the lady just kept quiet. I was not rude. I dont believe that achieves anything. But she had nothing to say so i asked her if she was just happy to pass me on to the technical division without even commenting on my dissatisfaction. She couldn't adequately respond. I find it distasteful and upsetting to go ahead & bill someone a 2nd time without the courtesy of a promised response. I would love to cancel my contract. It's been a horrible experience.