Nedbank Home loans

I have had Nedbank Homeloans deduct My homeloan twice this month. Leaving my family in a real state of despair. I work abroad and having to deal with this via email is quite infuriating. I was in arrears, but to my knowledge i had a payment plan made. Apparently nothing on record and due to this they refuse to refund me one amount. Is this how a big organisation treats clients. Makes me wonder. I also only have given permission through debicheck to have one amount raken off. Has anybody else had this happen to them. I am quite distraught about this. What do I do and dies anybody know somebody i can contact?