Debit Order ****

I have picked a debit order that went through from my account on the 31st of March 2016. I tried to reverse the debit order and stop it because I did not authorise it. I couldn't and I contacted my bank and I was informed that it has been loaded in such a way that it cannot be reversed. I was then advised to fill in a dispute form so that they can attend to my query. On the statement the contact no. that appear is *** and when I called the no. to get an explanation for the debit order I was told by the call centre agent that it is Nedbank number and they cannot explain to me my bank must call on my behalf they can only talk to my bank rep. I do not understand this because there has been several of these ****s and it is my account that is being debited I need answers. The debit appears as follows on my statement: sheatrdngRf***2 Sheat5313 R99 on 31/03/2016.