Yatra flight booking - Not getting refund of my flight cancellations request of booking reference no

I've cancelled my flights through yatra app within **hrs on *th December. But when I checked it in yatra app now it's showing "We cannot find any refund request for the reference number- *************". When I call yatra customer care they said send mail to yatra support email id, when I send mail to yatra support mail id then not getting satisfied reply from them. So now I want to take necessary legal action on yatra. So please register my complain against yatra.