BSNL Corporate Office Headquarters HQ:

Bharat Sanchar Bhavan
Harish Chandra Mathur Lane
Janpath, New Delhi-110 001
Dataone Broadband ‘1800-424-1600
PSTN Call Center ‘1500’ (in select states)
Sancharnet Help Desk ‘1957’
CellOne all India Help ‘1800 180 1503’ or ‘1503 1-800-424-1600