Jet Airways — not received refund for cancelled flight

Address:

Mumbai City, Maharashtra, 400059

I booked a round-trip flight of jet airways through paytm on february 2019. The scheduled date for traveling was 17th april and 22nd april. But the flight get cancelled by the airline itself and i get a communication from the airline stating, i will get the full refund from paytm. But it is almost four months i am waiting for the refund but not yet received it. Now paytm is saying that the haven't received the payment till now. I don't know what should i do and how much time it will take.