There is sometimes a period where a refund from an airline (or hotel) has been submitted/approved/completed (or whatever term they use) but doesn't show up in the side of the bank yet. It's frustrating since you're on the hook for that amount until it does.

I'd ask for the record of the refund from CX then wait another week and if it doesn't show up, file a dispute with AE forwarding the record to them.