Consumed 15 GB in 2 week

On the 31st July I noticed that my data was being consumed at an alarming rate. I noted that my R1700 accumulated airtime and 750MB of data was gone. Calling MTN help desk and visiting 3 MTN stores, gave me no indication that my data was being consumed at a high rate. Only when complaining to a further MTN store in Johannesburg in Mid August was I made aware that my account was at over R 10000 due to data usage. Many phone calls and emails to MTN giving me the run around were to no avail. A ***** case was opened and I did a comparison of URLs and itemized billing which I forwarded to MTN mentioning that the data usage was very erratic and inconsistent. In summary, from 29 July to 16 August, I had consumed over 15GB of data. According to MTN I accessed over 13 000 URLs with some cases of no URLS for the time period but yet over 100 MB's consumed at a time. In some cases 450 URLs for 4KB and others over 100MB. Since 22nd August I have swapped phones and SIM cards. I have had my contract changed from open data to limited data. I have had no feedback from MTN on their investigation. I am a pensioner, watching usage and I have been ****** by MTN.