unable to launch monthly debit order

We bought a vehicle through Wesbank in October 2015. We signed all the documents and also requested for a monthly debit order to be taken from our account. To date we have not had one automatic debit taken from that account. Instead, it is not paid, then they call us to tell us that the payment is in arrears, then my husband reminds them that there should be an automatic debit and that they can take a manual debit. This has been the status quo since we bought the car. In March they failed to debit us again (and the money is sitting there, ready to be taken). Now they have the audacity to let a debt collector call us to get info about our address etc, when it is their inability to get something as simple as a debit order right from their side.<br> We have asked them many times to check and make sure that everything is in order so that the debit can be taken...and the next month we will just have the same trouble again. I refuse to try and deal with their *********** call centre staff anymore. We want a manager to call us and explain why we are not being debited on a regular basis when everything else is in order and all other debits are going off that account without any glitches.