Flipkart — ordered phone not delivered even after promised delivery period

I made online payment to buy a phone on flipkart. But when delivery boy came he refused to deliver the parcel saying he does not receive the payment receipt and needs cod. I complained flipkart customer care several times but they respond with no clue saying payment updation needs some time in their system, every after their guaranteed delivery commitment.

Very frustrated with customer support. It make me think its not flipkart i called it as fraudkart