PSA: I recently made a bunch of aeroplan bookings and had to cancel/rebook many of them. Of 25 cancellations, Aeroplan failed to refund the points or taxes/fees for 3 tickets (on 2 different accounts) even though I received a cancellation/refund email.
It was pretty easy to sort out with them over the phone and they said they've seen this issue but I almost didn't notice as they were all cheap short-haul flights, and the activity section on their website isn't great so it took a bit of time to figure out which booking references hadn't been refunded. One was a full booking and the other was a booking where some passengers' flights had been refunded and 2 passengers' had not.
On my 25 cancellations their margin of error in not refunding was over 10%, so double-check any cancellations that you make.