Non delivery of courier by DTDC

Location/place: Noida

Name of company/service: DTDC

I have posted a courier containig a rakhi to Kolkata. The address and the phone no given were all genuine. But after a few days, after contacting the DTDC we got to know that the address was not found. This was completely unusual as the address was genuine and they did not even call on the phone no. given in the envelope. Instead they wrote that the address was not found and the phone no was not reachable. The rakhi was delivered back to me today. I would like to complain that why after giving genuine address and phone no why it has not been delivered.