Mfc's poor customer service

I called nedbank on the 24th of October to change my date to the 2nd of each month going forward after my debit order went of on the 23th October . The agent I spoke to didn't understand the billing system or t&c's then I requested to speak to the manager who assisted and advised that the date has been changed to the 2th of each month . On the 24th November I received an sms saying the debit order came back unpaid same day I called the call centre and requested to speak to the manager, the manager promised she will escalate this to the accounts department and he sent me an email to say it's done then on the 2nd December a debit order went off. On the 24th December I received another sms saying debit order came back unpaid and a call for call centre I again requested to speak to the manager coz this was too annoying now. The manager told me that he can see the interaction of the agents and managers I spoke to before , so his going to request for the previous manager I spoke too to call me, guess what I'm still waiting for that call and again today I received an sms. I'm not happy with how Nedbank Mfc deals with customers and I don't think changing a date can take 3months.