Making some assumptions here.... but if you are trying to buy something and have it shipped to Canada.......
- The seller must change the listing to include a shipping option for Canada
- The seller must change the listing to remove any restrictions for shipping to Canada
Changes to the listing should take effect as soon as the sellers clicks "submit".
If they make changes to their account, then they may have to click on an "update listings" option if there is one. I would assume it is similar to the old "policy" based shipping rules (that I miss) that had to be changed and then (re) applied to listings. I don't think any of this applies any more though.