Early debit order, bad attitude from call centre

I was behind with my nedbank personal loan, made an arrangment of which i honored, my payment is scheduled for the 25th of each month. 25th came and gone and double deduction was made, nedbank even sent me a sms thanking me for honoring my arrangment. yesterday I recieved money in my account whihc i needed for urgent things, however before i could even spend the money a debit order went on 09/03/2015. how can Nedbank deduct money 16 DAYS before it is due. I contacted the call centre and to add salt to the wound I spoke with a very impolite, uncaring and cold Again Phile, this agent didnt seem to care, a little compassion wouldve helped as Nedbank is in the wrong. When i asked him why Nedbank did this he said it is a system error, in his cold tone. I dont understand this system error! the money in my acc was reserved for other debit orders which have subsequently bounced, and now i have to wait 3-7 days for the money to be reversed, money which was never supposed to be taken in the very 1st place. how is nedbank going to console me regarding this gross inconvience, my ITC will be affected. I need answers as at the moment i have absolutely no petrol money etc...somebody pls explain