Originally Posted by
Transpacificflyer
Not an appropriate comparison. The "discounts" are provided for entirely different reasons. The coupon from the Bay is for promotional reasons. A discount code issued by Air Canada is for compensatory purposes. The failure of Air Canada to honour its discount code allows the airline to avoid providing the compensation it has agreed to. A coupon from the Bay is not issued for compensatory purposes.
I don't see it that way at all. OP buys ticket, uses discount coupon. Decides to return ticket(cancels booking). What's the problem? Coupon is good for 1 purchases and that's what OP did. End of story.