Amazon India — Delivery of my order

Address:	110009
Website:	www.amazon.in

I ordered redmi note 3 32gb silver color from amazon.In on 11th may 2016 with payment cod. The expected date of delivery is 16 may 2016 by 8pm. As per my order update and tracking it had reach delhi on 16 may at 11:42 am but till now (19 may 2016 22:52 ist) my parcel has not been delivered and no information from amazon side as well. I called customer service on 17th may and they are telling me it will be delivered within the next 24-48 hrs but still no delivery guy. My friend also ordered another phone on 18th may through flash sale and his parcel has been delivered (He's using next day delivery), i cannot understand why i had to wait for more than a week and more than 3days inside delhi itself. If they can deliver with next day delivery why not a week earlier order... I will hapily pay extra 100 rupees if they asked me to pay within the promise time but now i will even asked for 2rupees change...
Amazon delivery is the worst of the worst