Debiting account even after settling the loan! Rude & useless!

I paid a loan a month ago, the settlement discount still reflects outstanding & they still debit my bank account. When calls are made to teh Nedbank retail recoveries centre,teh agents are rude, dont give you chance to talk and explain, otherwise they bang the phone down and dont bother to respond. pathetic service, rude agents and down right useless. return my funds.