Man books Delhi-Vietnam flight via Flipkart, told his ticket doesn't exist at check-in counter

An X user claimed he booked a Vietjet flight ticket from Delhi to Vietnam's Phu Quoc Island via Flipkart, which turned out to be "invalid". The man claimed he was told the airline has no record of his booking after he reached airport's check-in counter. He eventually purchased a ticket at 3x the price, despite having ticket with PNR number.