Failure to Turn off Data Roaming Leads to Large Bill

Upon my return from a trip abroad, I immediately requested that data roaming be turned off. There was a problem with the data management of my account and I have now been billed for data roaming whilst in South Africa. I have queried this and received an email telling me the following: We can confirm the reflected charge was for authenticated access requested by your mobile unit and accurate with the volumes of roaming data invoiced. Please note that we are not in a position to advise on the activity that took place as the recording of user activity is not within our business module or a express RICA requirement, by providing URL or Website info never proves the billing but rather the billing process and the validation that the usage passed through the sim and device per report previously send, also important to remember that Vodacom bills volumes of data used and not periods of access and what kind of access takes place. All usage was registered on the networks via the SIM card and IMEI number of the device and therefore cannot be manipulated in anyway. The charges and information registered on the network is governed by ICASA to ensure fair practice. I AM DISPUTING THIS. PLEASE WILL VODACOM ASK SOMEBODY FROM THEIR ADVANCED DATA MANAGEMENT TEAM TO CONTACT ME AND RESOLVE THIS. IT IS NOT MY FAULT THAT THEIR STAFF MEMBER FAILED TO TURN OF THE DATA ROAMING WHEN REQUESTED. I HAVE A RECORD OF THE CALL