When you return the cover, use a TRACKED /delivery confirmed service.
If your seller is not in Canada this can be very expensive.
If you can buy the return shipping label through Paypal, do so. You may be able to save 5% to 17% off PO counter prices.
https://www.canadapost.ca/cpotools/apps/far/business/findARate?execution=e1s1
These are the business rates. You can use them even if you are not a business.