Hello yangry, welcome to our little forum on FlyerTalk!

Yes CX seats are hard to come by as it is, and even more so in the peak travel months of Feb and March.

You would have to call Asiamiles for assistance to look for seats as the online engine is not reliable. You may also want to try routing via Singapore, Sydney, Perth, Brisbane for onward connection to Melbourne. You may also want to consider Qantas.

Asiamiles also would like you to waitlist for the flights, and in due time, they will clear. That is one major advantage to be on Asiamiles.