Er, can try to cancel and update us here?

My personal experience:
Got my m2c plat in earlier this month (I already had the amex gold previously); asked for cancellation of m2c mastercard last week, (1st) CS said 'ok will proceed', called up on Friday to follow up and also mentioned 'last time CS said will proceed with cancellation', this (2nd) CS did not query and told me it's still in process according to system. Called up again today to get an update, was informed, after checking by (3rd) CS: 'can't cancel, we understand there was a request for cancellation sent, but rejected by management. Now all m2c CC after 1.9.2018 can't cancel just one card'. Called another (4th) CS afterwards and was told the usual 'now m2c cannot cancel either cards anymore'.

Wondering if anyone else did manage to get their m2c visa/mastercard cancelled post 1.9.2018 (especially if it's applied this year), at least some sharing would allow others to know that it can still be cancelled but depending on the CS..

Thanks. But I'd like to clarify, were your m2c Platinum CCs approved before 1.9.2018? Or just this year?

Eh, you mean you got your m2c plat this month and managed to cancel the m2c visa plat? By calling the normal CS line or the plat CS line?

My experience is the same as yours. However i feel there's still inconsistencies in their position on this.. Can still try, though chances may be slim..

I see. Wow thanks for the info.. Guess we can only try our luck to cancel the m2c visa/mastercard CC (without them giving the standard can't cancel either one card answer)..