ICICI Bank — Interest charges applied even after paying the outstanding bill

Address:	411001
Website:	www.icicibank.com

Hi,
I am using icici credit card, my credit card bill was rs. 10, 209.8.
I got mail from icici bank as payment reminder which was like

"payment on your icici bank credit card account no 5241 xxxx xxxx 6005 is due on 13/03/2016. You may choose to pay the total bill amount of rs. 10209.8 or the minimum amount of rs. 520"

This clearly states that the minimum paid amount to bank should be rs. 520.
I paid the bill of rs. 10, 000 on 11th march 2016 and due date was on 13th march 2016. Even after paying 10, 000 rs instead of the small minimum amount as specified by the bank ( i.E 520). In the next month statement i got interest charges applied on me.
The strange thing is that the interest charge was rs. 1001.60 for the outstanding amount of rs 209 (Only). This is just pathetic and unbelievable.

I wrote a mail to customer care but the responded "

You are our esteemed customer and we value your relationship with icici bank. However, based on the bank policy, we are unable to reverse any charge on your card account.
We regret our inability to comply for the reversals in the credit card account."

I have got the authorized mail from the icici bank regarding the minimum amount to be paid and thus want to challenge this decision of apply the interest charges on me.

Please let me know what else info we need to submit.