Worst service from MTN

I am a prepaid customer and every month I get billed differently. When I phoned MTN they say I was charged for content services, when I requested where I can find out what it was for I was given a number to call, the person checked and said there was no content charges so my question is why do I have to pay more every month. I never received an email or sms before the beginning of the new month so I know what my outstanding balance is. Now they have suspended my account as I only made a payment on the 08/01/2019 When I phoned MTN this morning again they keep on going back stating that in August last year I didn't make a payment, now my other question is if I didn't make a payment why didn't they then suspended my account????? I am so tired of MTN *****ing money from me.