You can fill up this form if they don't respond within timelines
http://mis.bsnl.co.in/pgs/internet/pgwebregn.asp
Check complaint status here http://mis.bsnl.co.in/pgs/internet/pgstatusintregn.asp
Or here in extreme cases
DIRECTORATE OF PUBLIC GRIEVANCES
http://mis.bsnl.co.in/pgs/internet/pgwebregn.asp
Check complaint status here http://mis.bsnl.co.in/pgs/internet/pgstatusintregn.asp
Or here in extreme cases
DIRECTORATE OF PUBLIC GRIEVANCES