GoCash not credited

I have booked a flight ticket from visakhapatnam to bangalore through goibibo website on Feb 16th at 4.04pm.As per the offer Rs2000 need to be credited in to my goibibo account as Gocash.I have contacted to the customer care no 18002081060 around 6 times and there is no use.They have been postponing the issue.My Booking Id of the flight ticket is N6ETE3BSN.