African bank robbing people

I called African on 2015/06/12 requesting a settlement amount,they gave me a settlement offer of R5063.49.I went and paid off that amount then called for account to be closed and requested a settlement letter.I did not get that letter instead i received a statement saying i am owing finance charges a month later.I called again requesting that the account be closed since i did request that before and have settled the account the agent promised me that they she will close the account but to date it is not closed.I got a statement yesterday saying that i owe R140 of finance charges,how do i owe wherelse i asked for my account to be closed?i will not pay that amount it needs to be written off and closed?is african bank so deep in debts that it wants to get money out of people by robbing them?i want this matter resolved A.S.A.P