Dtdc Courier Service - Packet not delivered

I courier a packet from Mohali to Ahmedabad on **th April **** at *:** pm through Dtdc international courier phase * Mohali branch and the charges paid for the fastest delivery that is Rs. ***. I got the assurance of delivery at the site on **th because the day after the packet booked was Saturday and Sunday. It was ok for me for delivery of packet on **th. Because it was a tender document that has been submitted on by Tuesday **th April ****. The booked packet was received at Ahmedabad branch of Dtdc on **th April **** but till date, the packet is not delivered and after calling so many times to customer's head Panchkula and branch no satisfactory answer was given by them. I tried to contact through emails also to customersupport@dtdc.com but they are too much busy that they are not able to reply. Please do the needful.