Airtel — my incoming outgoing calls have suddenly stopped

My airtel outgoing incoming calls have suddenly stopped i restarted my phone atleast 5 times and its intetnet is working but calls have stopped please see to it as quick as you can . I love airtel about its fastest internet quality and unlimited plans but this time what went wrong i have no idea?? plz see to it. It had been whole day i had no calls . I missed my important work of the day no one could connect me plzz help me .