For those who want it... This is the CX number I use when the US center is closed:

+ 852 2747-1888
(From the US 011 852 2747-1888)

You will get the greeting in Cantonese, hold on and the same info is given in English, or press 2 during the Cantonese greeting for the english menu.

This call center "seems" to be 24 hours.

Also, calls to Hong Kong even NOT on a calling card are not that expensive