Nedbank Loan

I took up a loan with nedbank on the 25th of July and I've been to nedbank ever since because they failed to debit my account weekly as requested that left me in arrears which I said I will settle in a double payments and Nedbank I payed half my arrears last week but this week they debited my account and took a full amount of arrears and it angered me because when I go to the branch they give me a phone to call loans department which is the most *********** department