Amazon .in/Delivery Courier - package not delivered

I had ordered one plus *t smartphone in exchange of my old phone on friday evening i.e. ** June ****. The delivery was expected on ** june i.e. sunday but the delivery came totally unannounced on saturday morning *:** am i.e. ** june ****. The delivery man said that someone will come in the afternoon since i was not done with formatting my old phone (He did not even wait). He went but i have yet not received my phone by today i.e. * july ****. All I have is two failed delivery attempt notifications on my amazon account. Moreover, I have already paid for the phone. I still do not have any clue if I'am even going to get my smartphone or not. The customer service, Amazon delivery service and dealer have been ignoring my calls and I don't know who to reach out for. I want my ordered phone to be delivered to me immediately.