Airtel — unable to call in particular location/receive incoming call

Address: Chennai, Tamil Nadu, 600030

I am using airtel sim with number [protected], i have been having this problem where i am unable to connect to the internet or call outsite. Also when some one else try to call me they are getting "person not reachable/phone is switched off". This occurs only when i am in my office in olympia tech park. I had no such problem till last week. But i am not sure what happened now. Kindly take it as priority and provide with a resolution.