Indian Postal Services — wrong product delivered

Address:

Varanasi, Uttar Pradesh, 221305

Sir my name is awadesh vishwakarma from tilanga jakkhini varanasi. I had ordered for a samsung galaxy mobile with cash on delivery which came through bhartiya dak seva. I have paid 3500rs to postman for that and opened in presence of postman and other people but there was no mobile inside the packed box. There was some brass sculpture. I said to postman that please return my money send this return but he said that i can return only after confirmation from my head office. Till now he has not returned my money neither he received my call. Please help me sir.