Sim is not working in iphone13

If the SIM isn't working, yes. That would be my next step. If they find that everything is working properly, then you may want to schedule a Genius Bar appointment at your nearest Apple Store (if one is close to you).

Here's a link to help with that process:

Genius Bar Reservation and Apple Support Options - Apple

Is your iPhone unlocked? Or is it locked to a US carrier?

Yes...what? What is "ind"?

You may need to verify the phone's information with Airtel to make the SIM work.