Home loan Pmt deducted after account settled

I settled my home loan account only to have the bank deduct Interest, management fee another installment, all against a zero balance. Note that FNB provided the settlement amount. I called to query and was told to complete a request form to have the installment reversed, nothing about the interest and management fee. <br> Honestly FNB, what is this about. You provide the settlement, then go on and have all these deductions and make it my problem to get the transactions reversed.