The Guangzhou call centre is simply awful! They are very green and can fool you around. Tried to call them twice and they could tell you two different things. One even told me CX has no conversation with their code share partners, which was a joke. I recall when I called MPC last year, they claimed they were CX staff instead of PCCW call centre, so I am not sure if CX still has its own desk handing calls. I called yesterday and was picked up by someone likely based in Hong Kong, though not that friendly, he was experienced enough to tell me those unofficial privilege discontinued a decade ago.
Regarding the English call centre, they are even more useless if your call involves pricing a ticket. They just have no clue of what they are doing at all despite they maintain a super helpful, friendly and positive stance. I miss the days when CX had three separate lines for MPC/AM, reservation and ticketing desk, but I know most other airlines are equally bad or worse.