DTDC Courier & Cargo Ltd. — Dispatching of courier to wrong address and now no response

Address:

Gurgaon, Haryana

Hii, My courier was sent on 6th July 2015 from DTDC Courier Office in Sec-15, Part 2, Gurgaon.Till Thursday my courier which had important college documents was not received to my brother at Modinagar(Ghaziabad) then I checked its status online and it was showing the status of "DELIVERED" IN Ghaziabad instead of the address mentioned.Then I went to the DTDC Office in Sec 15, Gurgaon and then the officials tried calling the delivery boy of Modinagar but he didn't picked up the phone.They told me that they will call me with the details within half an hour but that half an hour never came.In the meantime My brother and I called that delivery boy almost "50 TIMES" but he never picked up the call.Then I called at the DTDC office but they were not able to find any details about my courier and that delivery boy named "NITIN" and instead of finding out anything they gave me the number of Operations Manager of Ghaziabad.I called him and he gave the phone to some lady and till now they are not able to do anything.Now tell me that courier contained very important college documents and what should I do now as no person is responding.Who is responsible for this loss? This is the second time I am facing this problem with DTDC.Earlier also they had delivered my courier to some "OTHER CITY".Why have they opened the courier office if they are not at all responsible for their duties if the customers have to call 50-100 times times for their courier then its better to go and give the courier ourselves rather than using DTDC Services. Worst courier service.