Excessive Data Billing

I would like to make reference to comments on MTN Billing IT Web: I have noticed that during the month of May 2015 many people have been complaining about being over billed, I have also been over billed during the months of May and August 2015 and everybody is asking the very same questions that I have. I have been using my 2G data on contract for the past 8 years which was normally very controlled never exceeded, and then from Sep 2014 the over billing starts just on certain months not all the months, and after months and now a year of trying to get the matter resolved all I am informed is that your charges are valid, I would like to request MTN to further investigate all these complaints and see how common the problem is? How common the months are? People are saying I am using the same device/devices I don't have automatic updates/downloads how is this possible just on specific months? The itemized bill will probably indicate that 10G of data was used for that month and you are billed R5000, the URL will show the sites but does not say how much of data has been used for that particular site so how can MTN say that those charges are valid? My last ***