Breach of my contract

I took out a contract with MTN on 4 December 2014 for R999pm + insurance for R140 which is a total of R1139pm. On my contract it is very clear it has to be a TOP UP however MTN have charged me whatever they want and keep threatening to suspend my line even though I have paid R1140 every single month. I have queried this consistently for 16mths with MTN directly, calling and on FB, I have gone to other branches and particularly I have gone to the Oakfields Branch and spoken to Lisa Booysen (the owner of the store) with absolutely no resolve!!!! On FB MTN keep telling me to inbox them which I have done so many times (consistently for 4 mths) and NO RESPONSE!!!!!!<br> My biggest problem is also with the total blatant stupidity and lack of complete understanding by Lisa Booysen who keeps telling me what the problem is but has NO idea how to resolve it.<br> How can MTN even allow an individual like this to even own any stores????? Her employees, Mark Quinn and Mpho Masingo were the culprits here and have since left the store, however Lisa Booysen who was very aware of my problem has taken NO responsibility for her staff or my contract!<br> She has to be the most stupid, *********** person ever!!!<br>