Installment due after settlement, pillar to post

For some time now 2x a month every month Nedbank amended my home loan repayment. I called several times and got different answers each time. I then decided to settle my bond for less drama. After settling I now get an sms that my instalment has been amended with a figure attached! I SETTLED MY LOAN, WHY IS THERE A BALANCE DUE??? I called and again... NO ANSWER AS TO WHY... STILL WAITING