DTDC — Courier delivered to wrong person - DTDC Not addressing issue(K[protected]

We were supposed to receive a courier (K[protected] tracking number). However, we never received it and DTDC shows that it has been delivered to someone else. No OTP authentication or anything took place and now, they are not even receiving our complaint.
Customer service keeps telling that branch is not responding to them.
It has been 3 days and no response has been received, it was an important document and we are not able to find any trace of our consignment.