DEBITING ANY AMOUNT AS THEY WISH

I HAVE MADE ARRANGEMENT WITH AFRICAN BANK TO DEBIT AN AMOUNT OF R300.00. THEY STILL CALL ME EVERY MONTH WANTING TO INCREASE THE AMOUNT WHICH I AGREED FOR AN AMOUNT OF R350.00, THEY DEBITED THAT AMOUNT FOR END OF SEPTEMBER BUT END OF OCTOBER THEY GO AND DEBIT MY ACCOUNT FOR R567.00 WHICH WAS NEVER AGREED UPON, NOW WE CAN UNDERSTAND WHY PEOPLE DON'T LIKE TO MAKE ARRANGEMENTS TO PAY THEIR ACCOUNTS BECAUSE PEOPLE LIKE TO GO AND DO THEIR OWN THINGS TO YOUR ACCOUNT, WHICH I THINK IS TOTALLY WRONG. I DID REVERSE THAT PAYMENT BECAUSE WE DO HAVE OTHER COMMITMENTS. I REALLY DON'T SEE THE NEED TO PAY PEOPLE WHO CAN'T FOLLOW INSTRUCTIONS, BECAUSE WHEN WE PAY IT'S A PROBLEM AND WHEN WE DON'T IT STILL IS SO WE RATHER NOT PAY.