Default on EMI for 3 years with PNB car loan

to start off, I'll admit that this is a mistake on my/my parents' part and we are not faultless here. just looking for ways to mitigate the damage, if possible

my parents took a car loan in 2023 and the EMI gets auto-debited through NACH/ECS. we received a call from PNB today that there's a 1.49 rupee payment pending and that there's about 3000 rupees of interest pending

when I called the bank manager, they said that the EMI date is 31st and NACH debit is 2nd. we were completely unaware that this was causing a 2 day default every month and we got information of this just today. on call he admitted that it was the bank executive's fault to have set this as the date but he said there's nothing that can be done about the defaults reported to CIBIL.

is there anything I can do here in terms of escalating this with PNB and/or RBI (if relevant)? the interest amount is not really a big deal, the CIBIL hits are.

any and all help is much appreciated. thanks