Hi Neil. We called the Viking phone number listed in their material they gave us, but no one was available as it was a weekend. Also emailed them, but never heard back from them.
Honestly, this is on AA not Viking. If Viking gave you $500, that’s more than they were required to do so I would take it rather then risk them pulling it back.
You do not have to have a cruise line book your flights. If you wanted Delta, you could have booked them on your own. But this could have happened on any line. I have a friend that booked Delta to Croatia and their bags were lost for the first 5 days they were there and in a yacht cruise.