Airtel — 4g sim cardito

Address:

Hyderabad, Andhra Pradesh, 500081

My airtel 4g card has suddenly stopped working and shows up as 'no service - emergency calls only'. It was working fine, all this while but suddenly stopped giving the network signal. May i know what's the matter it's a pre-paid number and i have sufficient balance to make calls. I tried swiping the slots too but the problem is with the card itself. Please help.