UNACCEPTABLE

I FOUND OUT WHAT MY PAYMENT DUE FOR OCTOBER IS WHEN I SENT AN SMS, IT SAYS THERE IT WILL R428, I NEED TO KNOW WHY THIS IS, I DOWN GRADED LAST MONTH AND WAS INFORMED VIA AN EMAIL THAT I SHOULD EITHER DELETE THE DEBIT ORDER AND PAY IN THE AMOUNT DUE OR LEAVE THE DEBIT ORDER RUNNING AND ONCE ITS TAKES OFF THE R550 ON THE 2ND SEPTEMBER IT WILL AUTOMATICALLY LEAVE YOU IN ADVANCE. I WANT TO KNOW WHAT HAPPENED TO THAT MONEY, AS MY PAYMENT DUE THIS MONTH SHOULD BE FAR LESS, THERE SHOULD BE +/- R140 ADVANCE, I ALSO WANT TO KNOW WHY YOU ARE CHARGING ME R428.