Changing of Package without Consent

In June 2015 my son went for a upgrade on his phone. I am the responsible person so the phone was upgraded under my name. We went to MTN Northgate where we did the upgrade and he asked for a Top-Up. Firstly he was not given a Top-Up and we did not know it. I am working in Phalaborwa on site at the moment and suddenly in July 2015 my account went up from our normal account and in August 2015 it was as high as can go. Last week Saturday he went into MTN Northgate to check what is going on and now we are waiting for results. I phone Customer Care this afternoon and to my surprise I heard after me asking the lady how can they change my son's package twice if no one ever called me to discuss this matter with me. She suggest I must send MTN Direct a message from my phone so that they can call me I asked her how does she think I can send a message to them if my phone is off and it is off for more that a week now. She said I must go and borrow someone else's phone because she cannot put my call through. So much for caring and I am going to cancel all my contract's with MTN (which is 4 packages) for this is for more than 20 years.