Asus - Order was canceled without warning after 11 days because Asus Mobile was out of stock

I have ordered my mobile in Asus estore (Order Id :**********) and they have mentioned that they will be delivering the mobile within * working days but it has been more than ** days and they are dogging my questions and saying they will speak with the higher up regarding the query and delivery my product as soon as possible. And suddenly on the **th day evening I got a message that my order is cancelled without any prior mail Or extension. They are keep saying that they will escalate to the higher ups but still this issue has not been resolved. And they are now saying I need to wait for a month for the refund my money when I haven't cancelled the order from my end.

This is totally not right to cancel the order without prior notice and they haven't even contact me regarding my cancel order.
Why should I wait for the product eagerly and expect to be there in any minute and suddenly they cancelling after waiting for that long is not right from Asus support team.