Interesting. Seems that we're being billed for the canx fee in one transaction (new c/c payment to Aeroplan) and the refund will come from Air Canada (ticket issuer).
Considering you have charged all of the taxes, fees, charges and carrier surcharges associated to your original flight reward booking to a credit card, your refund will be processed directly by Air Canada. Your official refund receipt for your reimbursed taxes, fees, charges and carrier surcharges will be sent to you separately by Air Canada.
(emphasis in bold is mine on this, and below)
and then further below (attempted to reformat text as it'll show up - copy-pasting means formatting gets lost)
Fee Summary
$75.00 x [ 2 ] passengers $150.00
Tax Code(HST) $19.50
Total Credit Card Charges: $169.50 CAD
Look for "Aeroplan Canada, inc." on your credit card statement.
Apologies if this is old news to the more experienced on this forum - but I suspect there may be an increasing number of people that may be about to go through this for the first time, and so figured it was worth adding to this thread in case others come across it...