HDFC Bank — Credit card fraud calls

Today I received a call from +91-[protected] and they told me that certain services have been activated on my credit card and that they would be sending some courier which would have a discount card, holiday pkg and some gift. They also mentioned that I will be charged around 9k for this and there will be a refund of 6k in my savings account and 9k would be reflected in my next billing cycle. I felt the entire thing to be suspicious so thought of raising a complaint right away.