Standard Chartered Bank — outstanding amount increased even after cancellation request given of credit card

Address:

Gandhinagar, Gujarat

Dear Sir,

I was holding a credit card of Standard Chartered bank.
I have purchased a holiday package for 3N/4D from bank's telephonic sales department. 9 emi also paid by me and after that request to bank to cancel my package and refund me as per the terms. Bank executive informed me that as per terms paid amount can not be refund and i also agreed for that.
in the statement of month august they have charged me Rs. 750.00 for annual fees and when i called at customer care to cancel the credit card because initially information was given that it is free of anuual fee. bank executive registered my request on telephone and assured me that i will receive verification call in 48 hours and my card will get cancelled after that but i did not received the verification call till today, even they have not inform me the reason why my request was not processed?
Every month bank applies the late fees and penalty on card and amount made of Rs. 4776.24

It was bank's duty to provide the perfect information to customer on time so customer can settle the account immediately.
i have also send few email to bank but they have not provide correct information in their reply.
and bank was going on increasing the outstanding amount by applying late fee and interest.

i would like to get legal help against bank

kindly suggest me the way or do the needful