Sorry to hear about your poor treatment by Crappy Tire.
Unfortunately, you were one of many Canadians who had not yet learned that Crappy Tire has the worst return policies among major Canadian retailers.
And, to make matters worse, they fail to adequately notify consumer about these policies, so innocent consumers like you assume the policies will be the same as all the other retailers. Then, people like you don't find out until it's too late.
Some stores also add their own interpretations and extra rules, like every item needing to be unopened before it can be returned.
You can read more on this site about the different polices that they have, for unwanted items, defective items, battery warranties, etc.
Actually, you are lucky that they agreed to give you even a store credit - some customers get nothing at all, and are stuck with a non-functioning product.
But the real issue in your case isn't about the store polices at all. It's about the legislation for retailers (which can't be trumped by a store poicy).
If they sold you a vacuum that is supposed to clean wooden floors, and it does not do so, then you are entitled to a refund under the Sale of Goods Act. You can read more here:
https://www.canadiantiresucks.net/general-canadian-tire-complaints-chat/707-sale-goods-act.html
Ellen Roseman appeared on CBC recently, about a coffee maker that was sold as 'new' when it was actually used. The principle is the same: the item they sold you was misrepresented, so they are required by law to refund your money (and not just give you a store credit). Have a look:
https://www.canadiantiresucks.net/g...arketplace-concludes-canadian-tire-sucks.html
So, not only does Crappy Tire have the worst policies around, but they try to use them as an excuse to ignore the laws.
Are you really sure you want to buy anything there? Are these the kind of people you want to support?