Cell C *****

My 2 year contract with Cell C expired January 2015. I advised them I would like to keep my contract without upgrading to a different contract or phone. My initial monthly subscription was between R400 and R440. After speaking with Cell C upgrade department, we confirmed(Me and the lady from call centre) that my monthly amount would be R275(Basic R199 plus R75 Data Bundle). Middle of January I contacted cell c again because my bill was already R440, the lady then explained to my that Cellc are a month behind on their accounts, which I accepted as the lady explained to me. She specifically advised me that end of February my bill was to be R275. This morning I had a look at my bill, it is scheduled to be R509!!! This is unacceptable. I called them and they said there is an additional apple data bundle(to which I never agreed) and Pro Rata for January(Which no one ever explained to me as my contract only expired end of January). I am not leaving this here. I will not be paying the R509. If cell c does not sort this out there will be problems. I have never had problems with Cell c up to now. This is completely unacceptable.