Flipkart - Invoice not provided even after 14 days of purchase of product

*.Purchased a phone pixel *a on **th December ****. Phone turned out to be defective..
*. Sent it to Google Customer Support.
They demanded an invoice so as to send a replacement
*.. Placed several requests with the flipkart for the invoice as it was not present in the order email nor available on website to be downloaded.
*.Even after several days of purchase and * days after placing a request no invoice is received.
*. Have to let go of the phone replacement due to flipkart shoddy ways and for no apparent fault of mine.