Data Call Charges

On the 23rd of January I received an account of R4700 which R3600 was for data calls. I called in and spoke to a guy by the name of Thapelo Molekoa and explained to him that I had been buying data through my bank and transferring my MTN points into data. The last time I bought data was on the 14th of January. Thapelo still told me that he can see when I had loaded data onto my phone. He said he'll log a query for me, the issue will be investigated and they'll call me back (***). On the 3rd of March the above amount of R4700 was debited. I called in and spoke to Grace and explained the situation again. I was told that the query was never sent through by Thapelo Molekoa for investigation and that I have to log a new query (***). To date I have received no satisfactory answer as to why such a large amount was debited. I believe that I have been over charged and wish to get the matter rectified and the balance of the funds returned to me!