Incorrect billing, false contract information & I'm not receiving my statements

I upgraded my contract in April 2017 & I was told that the new contract will be R239.00 & that I will start paying end of May. But Cell C has been debiting me the old amount of R528.78. I called Cell C & Lerato told me that I am paying R21.50 for Itemized billing which I was NEVER advised about including the R239.00. She advised me that they are also charging for some data which is capped to R154.00. I was NEVER told about this when upgrading. Even if I add those amounts, it does not come up to R528.78. Cell C never cancelled my old contract & they are taking chances. I asked Lerato to forward me my statement 40 minutes ago, I'm still waiting. I have NEVER received my statements even after numerous calls to Cell C. I am so so Disappointed & I really hate what Cell C is doing to me.