You would think it would be perfectly reasonable, they cancelled the flight, so they should refund you.
But this is AirAsia, they cancelled flights on us too, sent us an email declaring we could have a refund or credit, we chose refund, 12 months later after so many times on their useless 'chatbot' we got nothing, so luckily as I had booked them via Australia, I got the local consumer protection involved, eventually they were forced to refund.
They are a one way valve, just like the one at the end of your digestive tract, in this case a one way money valve, once in their system, not possible to retrieve it.
When AirAsia X collapsed, all creditors, that is people who had brought tickets and received a credit (known as unsecured creditors), will get (they haven't paid out yet) 1/2 cent in the dollar.
AirAsia is most probably the worlds worst discount airline.
Good luck, I hope you succeed, please share your story if you do as many out there would also like to know how to get refunded from them.