Goair - Airlines refund

I booked a flight from Hyderabad to goa on goair airlines by goibibo app.my flight was booked on **th March,**** with phn nb*dwd.but my flight was cancelled no **th March by airlines due to some unknown reason and they promised me in a call stating that i will get all my refund to my bank account immediately but it has been almost * months and i didnot receive a penny yet.now it is showing that i am eligible for a credit shell but according to there online statement creditshell should be applicable only for passangers with flight datr on and after ** th march but my flight was on **th march .when i contacted goibibio customer service they are saying that airlines didn't give the money so they couldn't process the money to my bank account.on the day of floght departure i even received a call from goair airlines telling about the cancellation of my flight and they even promised me a full refund to my bank account immediately but when i asked for a confirmation they said that phonecall is only confirmation which is so unfair.and now it is showing in goair airlines that my flight was on ** sep but in goibibio it is telling that i am eligible for a creditshell.
I am so vexed up with this airlines
Please help me to get my refund from goirlines.i don't need any creditshell i only need refund to my bank account.