India Post — no proper response for speed post delivery

Address: Kamrup Metropolitan, Assam, 781001

With all regards i want to know why speed post (Indiapost) takes 10 days or more for just 200 km distance. Thereafter, customer care service is poor or null. They don't attend your call or wouldn't take issue seriously. The referred mail is an important document of my father's official leave purpose. Still i am trying to contact them from various alternatives available but still no response.