RBL Bank — unable to close my credit card

Hi
My name is chandana naveen and i am an existing customer of rbl using rbl bajaj finserv credit card. I cleared all my dues and contacted the customer care to close my card. The customer care people says, they don't have authority to cancel the card and they schedule a call with the escalation department, where i gave my available time in the afternoon session for them to call me, but they don't call me between the given time. As they are unable to connect with me they are not closing my credit card.