Standard Chartered Bank — unable to provide required info and shifting the blame to customer!!

Address:

New Delhi, Delhi, 110001

I am a salaried professional with good cibil score. I have been paying my credit card payments on time for past 2 years.in dec, i was not sure of how the billing is done and did not make full payment. Since last 2 months i am calling and writing to the bank to have somebody call me and walk me through my details to help close the account.
One representative called but she had no information that i requested - she could not even say from which date i am supposed to be paying. Now scb is just sending me sms / letters saying they tried to contact me but could not - which is a big lie and just trying to get past the issue by shifting the blame and responsibility on me.
All the time customers are not responsible for not paying. I am tired of calling their helpline, its a waste of time as i just keep putting requests. They call me after 7 working days and that too with half knowledge. It is harassment and trying to degrade my cibil score. As a working professional i cannot afford so much time.

Pls help!!!