How to block a lost RBL Bank credit card immediately?

I've held this card for 3 years. Quick reality check: the welcome benefit is good, the first-year fee waiver is easy, but from year 2 onwards you really have to work for the milestone benefits. Don't keep it if your monthly spend drops below the milestone threshold.

I've been a customer for 6 years. The biggest upside is the customer service. The biggest downside is the slow mobile app. If you do most banking on the app, test the app at a branch before applying — it's surprisingly old.