Nedbank unauthrised debit orders

There has been a debit order from my partner's account in the amount of R315.50 for over a year now. We have escalated the matter to Nedbank on numerous occasions. We visited the bank and they advised him to fill in a stop order form in February and these debit orders is still going off. Nedbank said that they are unable to trace the account or to stop this debit order. We are seriously considering switching banks as this is extremely frustrating as this accumulates to a large amount. We do not know how to escalate this matter further.