Myntra.com — Complaint against delivery agent

I need to complain against delivery agent. I recieved a wrong parcel from myntra, so made a return. For that matter I got approval from myntra customer care, if they approved my return, how dare delivery agent to reject my return. He took return with him, and then rejected my return continuously 3 days, and when i call delivery agent, he is not picking my calls. Need to complain such disturbing behaviour again delivery agent.