I had a very bad experience with Nedbank LTD,I called them and needed to settle the loan I'm owing I paid what they asked instead of closing the account they use the money to pay another account

I had a very bad experience with Nedbank LTD,I called them and needed to settle the loan I'm owing I paid what they asked instead of closing the account they use the money to pay another account. It is not the first time they do this to me. They even sent me a settlement letter how could they do this to me I'm trying to do good.