Nedbank takes what's not theirs

On the 01st of February 2016 a debit order with a reference \NRB\" with an amount of R156 went off my account. I only picked this up on the 06th of February 2016 while reviewing my online statement. I immediately phoned the contact centre to find out about this transaction and was nothing short of bewildered by the response. The debit order was deducted by Nedbank and according to the call centre agent this was only supposed to be applicable to business account holders but IT knew about the fault. If this is the case why not inform me for one and secondly why has it taken over a week for the refund to be auctioned."