I have a line for my i phone 17 from idfc bank and they charged me late payment fees for no reason

I have a line for my i phone 17 from idfc bank and i my emi date is 3 of every month this time i paied manually by the app on 3rd of octomber even i paid the emi on time they charged me a panelty for late payment , my bank account only had 50rs so only 50 debited if i had full amount of their charge they have beed debited that , it was a mental harrasment and emotional anxity as well for my cibil score And the customer care dont have any raal human to talk to