Terrible customer service

Disappointed. I recently took an MTN data SIM contract, Getting the SIM on its own was a hassle, I had to call and get redirected 7 times before they RICA it. I didn't even receive a contract or invoice in black and white till to this day. The bill was to be debited at the end of each month. The bill hadn't been debited for the first month, when I checked on my MTN app, it had said it was due on the 11th of this month, but when I check my outstanding balance it says it's 30days over due and that I owe thrice the amount that was supposed to be debited from my account. I hadn't even had the contract for longer than a month and all of a sudden I owed money to be paid over 3 months. I'm still confused about this. They don't even communicate. The customer service is terrible! I refuse to pay money I did not agree to. As a paying customer they don't respect me.