Consumer Redressal

I am having problem with my HDFC Bank credit card regarding finance charges.I made the payment long time before the due date via cheque but the amount was deposited to my ac after the due date.I raised up the matter and the late charge fees of Rs 700 was reversed but the finance charges remains there.There is a problem with the clearing system at the HDFC Bank.I know that the bank is at fault.They must instal the cheque deposit machines like the ones at Standard Chartered bank.I am ready to fight for my rights.I am having this card for the past 12 years and have not defaulted on any payment till date.If needed I will take legal action against the bank as they cannot take their customers for a ride.I hope they understand the need of the hour and rectify their mistakes.