In order not to be surprised like this about shipping costs it is essential that you read the entire listing, including the entire shipping details section. If you are looking on eBay.com it is even more important that you check if the seller will ship outside the US, many don't and run into problems as a result. The fact that you received an invoice show that your seller is willing to ship to Canada, but at a substantially higher cost. If this international shipping rate was mentioned in the listing, then under eBay rules, you agreed to it when you bought the item.
