If the seller is Not A Registered User (NARU) he has been kicked off the site*. The transaction is void. You cannot pay and should not even try. Be glad you were saved a lot of hassle and money. Move on.
If a seller is ignoring your emails, especially those asking how to pay, he is not a paragon of customer service. Although he may have indicated he ships to Canada, that may have been a (deliberate) error. If he is not paid within four days, and he does want to continue the transaction, he can start an Unpaid Item dispute. Don't panic, this should then make it easy to pay. It still means the seller is pretty sketchey, though.
You can go to the Resolution Centre (drop down menu-> Customer Support-> upper right corner) and start an Item Not Recieved dispute to get him moving. If he does not respond, the transaction will be cancelled.
*From time to time an honest seller who has not been updated a credit card, leading to unpaid fees will also be NARU. This is rare.
