Refusal to change debit order date

I never struggle to change a mere debit order date in my entire life as I did with a bank that claims to make banking easy and simple.I called the call center requesting to change the debit order date to the last of the month.They told me to bring a payslip or letter reflecting a change of the pay day.I don't have either of those. I don't understand though as far as I know paying arrangements are between myself and Capitec not with my employer.And I never missed any payment with Capitec.I don't understand why my account should get into arrears(as the call center agent suggested that I should deliberately let my account go into arrears) for something that can be avoided.<br> <br> Your assistance will be highly appreciated.