Unauthorised Debit Order

An amount of R99 was debited from my account on the 15th with reference MBS REWARD***9 SAGEPAY. I called Nedbank Current Accounts and they couldn't help me, The only thing they told me is that may be its a debit order that I forgot about. Why would authorise a debit for the 15th when I get paid on month end. The debit order reached my account with no funds, the debit order was reversed as there no funds and I was charged R130 for the returned Debit order. I have sent several emails to Pamela to have the R130 credited to my account as this was an authorised debit order and these people should never had access to my account in the first place. Hoping now nedbank will be able to help me in this regards