I can understand you and your dad's frustration as this is a large sum of money used by the device. Vodacom measures the data that is being transferred between the SIM and handset only and based on the data consumed bills you accordingly.
We do not look at the websites visited for billing purposes and therefore currently do not have technology in place yet to record URL information.
As you know, the iphone is a device that primarily makes use of data due to the applications on the device; these applications have a tendency to run without input from the user. I donít believe that your dad was browsing or downloading for the whole duration of the connection.
This tells me that it was definitely an app on the device that was running.
I cannot say why the data that was consumed was not calculated by the counter on the phone.
We cannot stop you from contesting this by using other forums such as ICASA, or from cancelling your contract.