Flipkart - Not refunding my money back FLIPKART

I booked a flight from delhi to patna for ** august ****. That flight was cancelled by the airline and I got a mail from the airline that I will get full refund for the cancelled flight, as the flight was cancelled by the airline. The airline sent my money back to the mediator flipkart. Now flipkart is not refunding my money back to me and continuously saying that we have refunded back your money , please contact your bank, I contacted my bank branch manager and given him the transaction id (given by flipkart and said this is the transaction Id of refunded money transaction done by flipkart side ). Branch manager no such transaction id exists and no transaction is made by flipkart to my account. Flipkart is keep repeating the same thing that they have refunded money and gave me a FAKE TRANSACTION NUMBER. From last ** days they are keep fooling me by saying same thing and they are not refunding my money at all.