First Flight Couriers — delay in courier service

Address:

Kolkata, West Bengal, 700013

A courier was sent from dumka, jharkhand to kolkata, west bengal on 27.12.2017. The courier has reached the destination on 03.01.2017. Kindly explain the reason for getting the courier delivered in 08 days, but the promised time was maximum 2 days by the agent. The charges are high because of the quality of service and the document being very urgent i trusted the company. But now since the document has not reached the destination within time i am bearing a huge loss.
The tracking id is u991b0368047