Ekart Logistics — No delivery on my order

I've ordered a phone on 7th October from Flipkart, FMPP[protected], and they made an attempt to deliver it and tried to install yantra app on my exchange phone and the guys failed to do it because he didn't know how to and took the delivery back. My previous phone worked just fine and that yantra app works fine aswell, since that day there is no update on my order and no second delivery attempt. It's an prepaid order and when complaint to Flipkart they have no clue about it. It's been more than a week now since I ordered phone was suppose to come on 11th and it's 13th today, there is still no update on it and I don't know where my ordered phone is.