Airtel — "unknown" (no number) calls while receiving

Address:

122001

Aietel have been a pain with my postpaid service no which i have been using for quite a few years no. Have been facing loads of problem in past few weeks. However this one is epic. When ever i receive a call for any caller details available or not it show as unknown for all the incoming calls and the call log also show as unknown with out any details.

Have tried changing the phone as well but still the same problem following up with airtel store as well as customer care but for almost 15 days, they have been good for nothing.. Could we please escalate the issue?