Myntra.com — non receipt of refund

Towards return of the product i bought from myntra, the refund amount of rupees 629.57 was not credited to my bank account.
I have contacted myntra via message but there was no proper response and only by providing rrn number [protected] the bank couldn't able to trace the payment.

Myntra is asking me to contact the concerned bank but they are ordering me to ask the sender (Myntra) as there is clearly no mistake or delay in bank side.

I'm confused and helpless.

I'm fed up trying to get my money.
I have contacted myntra and also bank customer care services for lot and lot of times. Even i went directly to bank for making complaint but they are clearly responding that the mistake was in sender's (Myntra) side. Im ready to go to any extent for my refund and i won't stop until i get my money back.