HDFC Bank — incorrect charges on credit card and refusal to close credit card relationship

Address: Mumbai

I have been charged incorrect processing fees. When they did not reply for weeks about that. I surrendered my credit card. I sent broken card to chennai with the credit card closure form. However, they are just refusing to close the card. Keep calling me every couple of days that "we have received your closure request and why don't you take another card". It is been 2 months i asked for closure. However, they are in no mood to do so. I wrote their emails, called them, wrote to rm and nodal officer. Even their nodal officer is equally useless.