Overbilled on FIXED contract

On 08 Jan 2015 I reported a problem on my Invoice for Dec 2014.<br> I explained that I had a 10GIG contract for R199 per month and that I have had it for a long time. (more than 2 years)<br> In the Dec 2014 invoice, R922.92 was deducted from my account and that it was a mistake since I did not request or authorise additional data bundles or an upgrade to my account.<br> In the past I would use the 10 GB and after that it would just not allow us to connect again.<br> The contract was for R199 and 10GB and that is it nothing more.<br> <br> Several calls were logged and no proper investigation was done or detailed billing supp****.<br> Nobody called me back - No Manager would face me.<br> This happened again in Feb 2015 without authorisation.<br> I logged a call again - 4 Now<br> I was shocked to hear the other calls were closed without proper communication to me.<br> I believe it is an error on Telkom's side and it should be PROPERLY investigated and I must be refunded. I have been in the IT workforce for 30 years now and know that programmatic errors CAN occur.<br> The treatment that I have received from Telkom Mobile is appalling! <br> Is there NO senior manager at Telkom Mobile that have the courtesy to call me back?