BSNL - Land Line — Phone line is not working last 50 days ago.

Dear Sir,
My Telephone no is:[protected]Tirupur) is dead for the past fifty days. In spite of booking of complaints no action is being taken to rectify it. Also i will compliant directly at veerapandi exchange and Tirupur bsnl office. But no action still now. i am very dis appointed. bsnl customer service is very very poor. Also i am missed lot of export orders. Still, they are claiming the bill for telephone. Kindly advise me what to do next?