Urgent payment will be stopped

I have 4 phones currently with MTN which was all on a top-up contract 6 months ago I renewed my son's phone and asked to have he same contract with top up but just with another phone. This was all done telephonically, my bill then went up and I queried it and they said my phone is on a Anytime 200 account. I then said to them that I want the recording but with no success I have been given the run around to phone everyone and no one can help. I then out of good will paid R5000 and they never corrected it. I am hit again with a massive bill with no one doing anything about it. I will however stop my payment as I will not pay again MTN just want to sell but NO after service. This is ridiculous, I want someone that can help me ASAP this is unacceptable and I should think there would be one contact point to raise concerns and not been given tel numbers and when you phone they just give you another number. This is enough