First, let's make sure that is the actual problem.
When you listed were you able to use Calculated Shipping? If you could then you listed on eBaydotCOM, but you offered shipping to Canada (or worldwide) and your listing will turn up here (and in eBay Australia and eBay India and eBayGermany.)
If you normally use Flat Rate Shipping did it mention USPS services or were they Canada Post services?
EBayCanada allows both US and Canadian dollars to be used. And if your item was made available to the USA, then you will get visibility in Search.
So you could just let it ride.
But if you are really worried, end the listing. What will it cost you? Thirty cents? Less?
Unfortunately, you cannot relist directly onto another site. So cut and paste your important information into a text document. Go to eBaydotCOM (just change the URL in the address line up top there) and redo the entire listing.
