Unauthorized Debit Order.

I have an existing home loan account and at the end of October I called in and requested that my debit order date be changed from the 28th to the 25th. I then received two emails on 2nd November and I requested that the Consultant Xikombiso Maluleke call me because I needed clarity on the two emails. After speaking to her she indicated that the debit order will be effective on 25th December and I should make a transfer on 25th November. After making the transfer FNB still debited on 28 November. When I called in to enquire, another Consultant, Mishka, informed me that I should have waited for a written confirmation before making a payment. The unfortunate part is that FNB is always quick to shift the blame to their clients instead of rectifying their mistakes, and this is not the first time they are doing this.