It's easier nowadays to use their WhatsApp service (+852 2747 2747) - which I've used a few times (in English) and the responses are quick and efficient (I don't know if it's because I'm a Diamond Member or if my requests are not too difficult). Sometimes the agent is online at the same time as me and I can do a back-and-forth conversation with them on WhatsApp.

Info below:
https://www.cathaypacific.com/cx/en_HK/contact-us.html