Well I haven't heard from "Customer Care" yet. I assume I'm in the general holiday backlog queue. But I did receive an automated email:

PLEASE CONTACT QANTAS AIRWAYS WITH REGARD TO YOUR UPCOMING
TRIP. YOU NEED TO ADVISE A NEW FORM OF PAYMENT AS THE CREDIT
CARD PROVIDED WAS DECLINED BY THE CREDIT CARD COMPANY.
YOU MAY CONTACT QANTAS AT ONE OF THE FOLLOWING NUMBERS.

I know this is automated, and probably prompted by them trying to credit $200 to my credit card. But from an angry customer's perspective who would be less than understanding they would be saying "AND NOW YOU WANT TO CHARGE ME MORE???????"