Useless staffing and no sense of pride in their job

Hello there, I am experiencing the worse nightmare of my life with MTN SA. I am a contract user, in the past I used to walk to MTN outlet to make cash payment ; lately I realised that it was convenient processing payments via Electronic fund transfer (EFT) without realising that I was looking for troubles. I started that in July 2017 and since then MTN billing department never updated payment in their system. From time to time my services are subjected to suspension till I can contact their useless contact center who really have no clue of what is happening. The best option at that moment is to ask for proof of payment and reopen the line at that moment then few days later the same nonsense is repeated. Now and then I am receiving threatening SMS and mail from MTN advising me to pay . I never defaulted any payments , seriously MTN is one of the worse service provider I never known. They are such a bunch of useless in their office. Can't believe that up to three months nobody is able to update payment accordingly, they are causing me so much prejudices.