Overcharged for Data Usage

For the past 3 months I have been overcharged on my a/c. If you check my billing history you will see that I average at about R629.50 but now my bill is sitting at R2000+. When i queried this 3 weeks ago with a Lindiwe Ngoni ref no: *** I was told my a/c was high because of data charges, which is absolutely ridiculous as im in a wifi zone 90% of the time and if I do have to use my internet without wifi it will obviously come off the free data given to me every month. She told me the matter would be investigated, up until now I still have not recieved any feedback. I then emailed mtn twice last week ( ref EQ***) and still no reply. <br> Secondly I spoke with a Nandiya also 3 weeks ago quering why I am still been charged for Blackberry Internet Services every month when I upgraded my blackberry fone to an ifone on the 7 May 2012. She told me I would be reimbursed... Still waiting...<br> This matter needs to be sorted out asap as I am now livid and every time I try and phone mtn im left holding on for nothing less than an hour<br>