Data mounting up even when switched off on phone

<p>On Friday I received an SMS sayingi had less that 89`MB data on my phone less at around 8:30am I was at home wrapping presents, at 1 om I received another SMS saying irregular DAta activity had occured andf I owed 4328.01 I immediately called the call centre and was told this must be an error and that a call would be logged and that I should switch the cellular data off which I did immediately. They said it has been refereed to the technical dept and sent me and SM reference number A2-20C2-1CF1ZR. I was told they would get back to me within 48 hours. Nobody has been in touch with me and my accounts lady tells me the bill as of today is over 7000,00 despite me having turned off my cellular data on my phone. How is this possible? It is logged as a problem and yet they let it ring up another R3000,00 this is highway *******! I want this resoved imediately and the excess data reversed from my account. </p>