Postpaid family plan mess

Me and my family decided to opt for a postpaid family plan for 3 members ₹999. We changed last night, my number is the plan manager. After switching to postpaid I am unable to make calls or send sms, yet mobile data works perfectly fine and I can get incoming calls and texts.

Went to the Airtel showroom today, they said the SIM has to be changed (The card was purchased by a relative who's dead) so name change has to take place and for that all our numbers have to be changed back to prepaid but only after 30 days.

Is there any way this could be fixed in any other way???