Cell C
No response from CellC on invoice dispute logged

I have made two phone calls and send a e-mail to CellC, but still they have not resolved my Invoice for September 2013. They overcharged me for the month on my 3G data usage at a rate of R2.90 per MB. Clearly their system doe not work, and even escalating the matter has not delivered any fruit.
Now if the funds is deducted from my bank account should this not be considered?
What now CellC? Where is your customer Service.