Domino's Pizza — order failed but no refund, nor acknowledgement for reversal

Address:

Hyderabad, Andhra Pradesh, 500084

Placed an order for 523 rs via Domino's app and prepaid the order through Amazon pay. The order 'failed' not cancelled and didn't even get an acknowledgement message for reversal of amount. Neither do I have my refund nor my order. Please look into it. Placed two other orders which got accepted but this one was failed, not cancelled. I called customer care and they bluntly said that system is down so they can't help.