Excellent idea!
See their web site at
Government of Ontario, Canada / Gouvernement de l'Ontario, Canada
Keep in mind: there aren't laws regarding unwanted goods, but there are laws requiring refunds for defective items, or items that don't perform as advertised/described. And the stores can't just post any old policy they want regarding defective items, and use that as an excuse to deny a legally required refund.
"If you want a refund or exchange based on an unfair practice, you have legal rights and the retailer must address this issue."
(Crappy People will tell you that you have to settle for a repair, so find out for yourself!)
You can also call them at 416-326-8800 or 1-800-889-9768.
They can fill you in on the implied warranty for merchantability, unfair practices, and so forth, and help you get the refund.
Based on the stories on this site about suing Crappy Tire, the store may force you to file the lawsuit first, and then give you the refund. (Which explains why there is so little case law - Crappy Settles Out of Court!)
Best of luck!