From the T&Cs:

Qualifying purchases for this offer:
To be eligible for one (1) $125 statement credit, you must have a total of two (2) qualifying purchases that include one purchase of $150 or more (after taxes) using your registered Card at aircanada.com AND one purchase of $150 or more (after taxes) using your registered Card at one of the other participating Canadian merchants during the offer period. The qualifying purchases must be completed & posted to the Cardmember account by November 22, 2013.

1. One (1) qualifying purchase at aircanada.com must be $150 or more (after taxes) and charged in full to your registered American Express Card.

The following aircanada.com purchases are not qualifying purchases and are excluded: Car rentals, hotel bookings, Air Canada Vacations and eBoutique purchases made through aircanada.com. Bookings made through travel-related web sites and any other channels that are not made directly on aircanada.com.

The following are qualifying purchases and included for this offer: Bookings made by travel agencies at aircanada.com/agents, including bookings by Centurion Travel. Flight Passes purchased at aircanada.com and Air Canada gift cards purchased through aircanada.com.

I'm guessing that you weren't happy about GCs being excluded. Hope this helps.