Cannot change homeloan debit order

Nedbank homeloan refuses to change a debit order from to a husbands account to pay for homeloan because he is not named on the homeloan account. We are trying to make payment so our loan does not default and they are unable to help How useless is the Nedbank. We want to make payment on a loan and they do not want to assist to change the payment details and accept our money. The loan must default first.