Airtel — I'm complaining about the network issue

I'm using my Airtel number for past five years and suddenly yesterday the signal have been lost and showing emergency calls only sign and often it is showing notification saying "no voice service". I'm unable to make any calls even for the customer service since yesterday. And I've tried to file a complaint on the Airtel application but I couldn't and I'm not sure whether they are concerning about such complaints raising everywhere. What's the problem with Airtel network?