India Post — post not received at the given address

Address:

house no 100 guru cottage chemmbur opp inlaks hospital, 400074

My letters in the name of miss p k lala, address house no 100 gurucottage chembur 400074 have suddenly vanished i;
Letter vto the post master given say he does not know any thing. What to do this is happened in the last twelve to sixteen months.
Eithet the post nis stolen or hes been readdresed by crooks,
Waiting for a proper action.. Help