Incorrect banking details debited

My first installment for my new vehicle was meant to go off on the 2nd of Jan. Nothing went off. On the 3rd of Jan I called your call centre and spoke to Nico (***). Apparently the debit order returned and when I confirmed my banking details it turned out that you guys loaded the incorrect ones. No sure how that happened because you have bank statements from me and I gave you my banking details. Nico said he has corrected my details and the debit order will go off on the 4th. Today is the 5th and still nothing. So now this reflects badly on me when actually its not my error. Please urgently have this rectified as its not acceptable!