Returning a Debit Order to get service

I have called Sanlam previously to change my bank account details. I was told that it would take a month and that I would be called back. As nothing happened I allowed the debit order to bounce and, guess what, I immediately received an sms that I owe money and that they on top of it have now had the audacity of reporting this issue to the credit bureau.

When I called Sanlam they were, curiously enough and contrary to previous advices, able to change the bank account details on the phone. DOES THIS MEAN THAT ONE ALWAYS HAS TO BOUNCE A DEBIT ORDER TO GET SERVICE?

I FURTHER DEMAND THAT THE CREDIT BUREAU LISTING IS REVERSED IMMEDIATELY IN THESE CIRCUMSTANCES. \