DTDC - Package not delivered

I am a student at IIT Kharagpur and I needed to send a document on an emergency basis to Kharagpur from Kolkata. I approach DTDC office of Park Street at Kolkata and take their guaranteed next day service at their mentioned price. I was assured of delivery next day by ** am and the reciept also mentioned the same. The next day it was * pm and still the package was not delivered. After atleast ** phone calls to various DTDC centers, it was discovered that the package was still lying at their Kolkata office and no one was able to tell the reason behind it. The document was very important and it costed me a scholarship amount of Rs * lakh. The service and behaviour that I got has ensured I never use DTDC again.