MTN contract is a ****

I was made to pay R520 instead of R275 in April, so I reversed it and asked them to explain what is it for and until today I never got the feedback but I was told to pay R275 while they still investigating. So end of June I decided to settle all those payments, only for my account to be suspended on the 10th of July. MTN wants me to pay twice a month, I must pay on the 8th and on the 25th. They can't help me even at their stores and they don't want to explain to me why must I pay so much money