Kotak Mahindra Bank — Credit card settlement

Address:

Thane, Maharashtra, 401105

I was using kotak credit card since 2014, i made all my payments on time but still my credit limit was not enhanced (This is not the matter), in 2016 i changed my company & salary from company was irregular hence i was not able to make my payment on time, than suddenly a guy from kotak bank came and informed me about settlement amount was 13000 inr, i made the payment of 13000 inr with late payment and service tax, my account should be closed, but still kotak bank is sending me emails, sms to make payment.
Till i dont have a proper answer for my email, calls, social media. Now i dont know whome to contact.
Worst bank experience in lifetime