[Resolved]  Airtel — airtel network always out of range or not reachable

My friend is using airtel post paid connection for quite long period and he was satisfied with the service but last few months he face issue with the service.His no.([protected]).Whenever someone call him, it is always found out of range or not reachable or directly disconnected .He raised so many complaints regarding the same by calling custumer care executive .But it was not actioned yet.The purpose of having mobile is to reach the person in urgency.But because of this network issue, if he is nearer to the person who is calling him, the caller would get only not reachable voice message.Please action on this as soon as possible

Thanks,
Valar