BAD SERVICE AND CANT KEEP TO THEIR PROMISE

I was billed for data and airtime that I never used however the airtime was sent to other people from my phone that's using the same network as me. In spite of my numerous emails since June-December 2015 nothing happened. I then went into MTN head office on the 2nd of Feb 2016 and showed all the emails to Mario and Andre from the legal department. I spend the entire day to sort out my queries and two days later I received an email from Mario Singh from ***** department stating that a credit of R3206.01 will be passed. To date my phone is still blocked since Oct 15 and I am still paying the normal monthly TOP UP contact of R499.00 but I still have no usage of my airtime and data as per the contract. I have NEVER requested any special data on my contract ! MTN has failed to explain how a top up contract can send airtime and also that exceeds the allocated airtime once it has depleted . When I needed more airtime/data I had purchased prepaid airtime myself . HOW CAN A TOP UP CONTRACT TURN INTO AN OPEN LINE THAT DOES NOT HAVE A THRESHOLD?? ALL THIS HAPPENED WHEN MTN WAS ON STRIKE APRIL15 NOW I HAVE TO SUFFER. I NEED MY LINE OPENED TODAY AS I HAVE PAID MY MNTHLY SUB FEE!!