Kotak Mahindra Bank — unsolicited calls for credit card

Address:

Bangalore, Karnataka, 560076

Hi i was a customer of ing vysya bank since 2004. After the bank got acquired by kotak mahindra bank, i am getting unwanted calls for credit cards daily from the last 1 year. I would have blocked atleast 100 numbers but still i continue to get the calls from different numbers. I have opted for dnd with airtel but still i am getting the calls. Please suggest me on how to get away from these unwanted calls. Is closing the bank account the only answer?