Airtel — mobile network issue in marathahalli bangalore area

Address: 560037

We are facing lot of mobile network issue in our area (Munnekollal, marathahalli). Signal is very bad and to take calls we need to come out of apartment.
Mobile shows full network but incoming and outgoing of calls won't work, this is not an issue with specific mobile. We have multiple airtel numbers everyone are facing same issue in our apartment. After raising complaints also this problem is not getting solved.