Unauthorised upgrade no response from MTN

My wife went to MTN Wonderpark to do an upgrade o n her phone on the 18th July 2015 and was informed that an upgrade had already been done on that number on the 12th June 2015 at Davenport Square Centre. She informed the agent who was assisting her that she has never authorized nor was she involved in that upgrade and the agent advised her to contact MTN Customer care which she did. MTN then asked her to make an affidavit and mail it together with her ID. These was done and mailed on the 19th of July 2015. The problem is up to date we have not received any communique from MTN informing us of the progress of this matter. We send two e-mails last week trying to check the progress but no response to both mails and now my wife is frustrated and it seems MTN doesn't care. The least they could do was to contact us and give us information about what is happening to this matter. The number in question is *** and my wife's name is Ouma Shirley Rammopo and my contact phone is ***. We have the name of the salesperson who effected the upgrade and he actually called my wife asking her if they can sort out the matter without involving MTN.