State Bank Of India [SBI] — cancellation status of sbi credit card

I was provided a sbi credit card eight months back without any charge from state bank of india, burnpur, wb but i had not used the card. I have also not generated the pin for the card. Two months back i called for the customer care of sbi and after taking my request for cancellation they informed me that i would receive a cancellation letter in my communicating address after 15 days of cancellation. But till now i have not received any letter or communication from their end. I again made a call in the customer care no. But could not go for the perfect option for the enquiry of the status of my card for cancellation.
Please help me out as i want to get the card cancelled.