Thanks for everyone's advice so far.

I already did "dispute" the refund with AMEX. AMEX said the "refund" will stay on my account until the investigation is completed.

Update is I got an email reply from [email protected] (not sure to which inquiry since I sent multiple emails and phone calls) that based on the conversion rate I should have gotten US$1000. Did not address my explanation that I got over $100K. I can't believe they are dropping the ball this badly.

If this drags on for several more days I may end up having to reach out to one of the bloggers haha.