PayTM - Refund for flight cancelled by Airlines

I had booked a flight ticket of Air India for * people through Paytm on Nov ** but the flight was cancelled by the Airlines and the full refund was initiated but it has been *.* years and still Paytm has not refunded my money. I have even received a written communication from Air India that they have refunded the money to Paytm on *th of Feb **, still Paytm is not refunding my money. Every time they ask me to wait for sometime. Yesterday on call Paytm exexutive said me that they has initiated the refund but it failed and then i got a mail from Paytm that refund failed at the payment gateway and asked me to share the updated bank details but today when i called them they said that they haven't yet initiated the refund. Please help.