I finally heard back from central refunds - but that only because I reached out to their social media team:

Kindly note full refund was processed from our end for the below tickets. Please be advised that ticket was issued in CAD currency ,the bank has then converted this to USD at their own exchange rates.

Request you to please liaise with the card issuing bank.

I spoke with my bank and they will deal with it- I will have my $103.94 refund in the next 90 days.

Thanks all for your help!