INCORRECT DEBIT DATES

I HAVE APP**** FOR A ADSL LINE IN MARCH. WHICH IS WORKING FINE, BUT UPON DATE OF GIVING MY BANKING DETAILS THROUGH, THE CONSULTANT DEALING WITH ME ASKED WHAT DATE I WOULD LIKE MY ACCOUNT TO BE DEBITED. SO I SAID THE 20TH OF EACH MONTH, WHICH IS MY PAY DAY. IN MAY 2015 MY ACCOUNT WAS DEBITED ON THE 19TH SO EXTRA BANK CHARGES HAS TAKEN EFFECT AND MY CREDIT RATING ALSO AFFECTED. ON THE 29TH OF MAY I RECEIVED A STATEMENT SHOWING THAT NOW MY ACCOUNT WILL BE DEBITED THE 18TH OF JUNE 2015, WHICH IS ALSO BEFORE MY PAY DATE. SO I THOUGHT ITS FINE LET MY CONTACT TELKOM AND ASK THEM TO MOVE THE DEBIT DATE TO A LATER DATE, BUT THE RESPONSE I GOT FROM CAREN MUGOMEZULU WAS THAT SHE CAN CHANGE THE DATE, BUT THE DEBIT ORDER CHANGE WILL ONLY TAKE EFFECT IN ONE MONTH, AND THERE IS NO WAY TO STOP THE DEBIT ORDER. I ASKED IF I COULD LOG A CASE SO THAT THIS CAN BE RESOLVED, BUT I WAS INFORMED I COULD NOT LOG A CASE. I DO NOT FEEL THIS IS ACCEPTABLE AND IF HELO PETER IS THE ONLY WAY I CAN GET IT RESOLVED, I WOULD APPRECIATE THAT MY DEBIT ORDER DATE CAN BE CHANGED WITHOUT BEING CHARGED.