extra debit

On the 9th Jul I paid up my loan acct that I had with Nedbank, on the 27th Jul I called Nedbank to be told that the funds had not been allocated to my acct,I requested a confirmation letter that the acct was paid up and the debit order was to be cancelled,from the 26th-- 31st Jul I was calling Nedbank Personal Loans dept,promises were made by D****ha,Gugu,Khuselwa and Cleo that the debit order was cancelled and the confirmation letter was to be sent,till today I haven't received the letter and to make it worse Nedbank debited my acct on the 30th Jul and I've requested to be refunded my money urgently and still that hasn't happened. I want my money back and whatever is owed to me by Nedbank urgently.