Volercars — haven't received my refund

I have booked voler car on 19th July and due to some reasons the booking was cancelled and I called up the customer care 5 times till now and every time I ask about my refund they due to some technical issue at payment gateway they couldn't process my refund and it will be done by the end of this week which had never happened.
I have a legitimate proof (call recordings and booking id) that they are manipulating consumers and giving false promises.