MTN Service is appalling!

I am doing this review out of complete desperation and really not knowing where to get assistance from. My son and myself have MTN cellphones and my son left to live in the Drakensberg over a year and a half ago where MTN does not work. He was over his contract period so it was cancelled. Months later I realized it was not cancelled to called again to cancel and again and again. I wrote emails to MTN and went to the stores, (of course they cannot help you, only the call centre can)! I have called the head office many times and just this morning being the final straw have been on hold for 45 minutes to be cut off once again. PLEASE can someone just help me here, you are impossible to deal with and every month that ticks by I am paying for a cell phone number that has not been in existence for 11/2 years now - what on earth!!!!!!