********** upgrade on my MTN account

On the 28Oct '15 I received 2 sms's from MTN, stating my payment details changed and my contract was upgraded. I had not done either.<br> I phoned MTN on the 28 Oct '15 (REF ***) to query, I was told that this was ***** and that they would investigate and that this would take about 4 weeks to investigate. I was not required to provide anything else. <br> I phoned again on 4 Nov '15 (REF ***), to alert MTN that the ***** was actually on my Router account. They said it was still being investigated and I was not requested to do or submit anything.<br> On the 18 Dec '15 I requested an update as I had heard nothing.<br> On the 21 Dec I received and email from MTN stating they now require a case number, affidavit and copy of my ID so they can just start the investigation. Not once before was this mentioned to me.<br> 7 weeks later and nothing has been done. I am being billed for an incorrect amount due to the ***** facilitated by MTN, not me. I am now inconvenienced due to MTN's negligence and inadequacies. I need details on how and where this ***** occurred and for this matter to be resolved immediately. <br>