Unfair late payment penalty by ICIC Bank

I have been ICICI Card holder for more than a decade and paid all the dues withing the last date of payment. Last month, my bill was Rs. 45735.55. I paid Rs. 44,700/- in two installment. One installment was from the JET Airways as a refund, I paid the remaining. Due to miscalculation it was about 1000 rupees less than the due amount. To my surprise, an interest rate of Rs. 2391.67 has been charged in the next month bill. The bank has not even informed me that your due amount is short and you will be charged interest on entire due amount. This is utter nonsense. If at all interest rate should have been charged on the remaining balance and not on entire due amount.
I request, the forum to take this issues so that no honest customers are penalized inappropriately.

Ajit Kumar
ICT Matunga (E), Mumbai 400019, Maharashtra
Email: axxxxxxxx2@gmail.com