Billdesk — gulped down 7500 bucks and not responding to mails

Address:

Faizabad, Uttar Pradesh, 224001

I attempted to pay the fees of neet pg examination on 1 november 2017 first via bank of india then via state bank of india. Both the times amount was debited from my account while the transaction was unsuccessful from merchant's side.
This scam of a payment gateway took the money twice against the same bill no.
When i complained, i was told that we have fwd the issue to merchant to resolve... It has been a week and they have stopped responding to emails also.
Upon contacting the bank i was told that the issue was with payment gateway which was billdesk but those scamsters don't even respond to mails.. I am fed up
I have been scammed for 7500 bucks with the amount being 3750 rs debited twice from different accounts