India Post — Post not arrived or misplaced

Address:

General Post Office, Shimla, H.P - India. PIN- 171001

I had sent an ordinary post through General Post office Shimla more 2 months ago and it hasn't yet reached there. It was supposed to be sent to PANIND SERVICE UNIT #5, Site IV, Vikaspuri, New Delhi- 110018 India.

The post contained important documents in it and it hasn't reached there yet.
I inquired there in the post office and he says that they have nothing to do with it and can't do anything about. Neither they can track it nor anything else.

Please help me.