REALLY BAD SERVICE MTN

I am having HUGE issues with my account with MTN. Last month I paid on the 16 th October 2020..... which I arranged to pay later the month. The the amount of R700 was reversed by MTN..... and on 1 November 2020 an amount of R1400 went off from my account. Now im in arreas R700.00 and I have been disconnected.... WHY.... HOW......