The first thing that comes to mind, - are you certain the seller ships to Canada?
If the seller ships here and there was no specific fee stated in the listing, - I sure hope you inquired about that before bidding.
The second thing I would consider is that this is the weekend and sellers might have real lives in which something more captivating than ebay has them temporarily preoccupied. One thing you can be sure of, - sellers like to be paid right away, so as soon as a seller sees a request for an invoice s/he invariably sends one off.
If you inadvertently buy from a seller who does not ship to Canada, - first thing to do is send a gentle apology to the seller outlining how your bidding enthusiasm blinded you to that Ships to: phrase appearing on every listing. Ask if s/he would be willing to send it to you anyway. If the seller does not seem particularly accommodating, perhaps you could suggest a Mutual Cancellation. After all, if the mistake was yours, you want to be reasonable. That way, when the seller issues you the Request for Cancellation, the instant you click to agree you are no longer responsible for payment.
The down side of buying things where there is no shipping fee nor a previous agreement is that you may find the seller charges a whole lot more for shipping than you had anticipated. If you cannot renegotiate more pleasing terms, then again you may wish to propose the Cancellation.
For now, however, I'll assume that the seller is simply busy. There is no point in sending more requests. If he is receiving them, more will only look like nagging. If he is not receiving them, well, a waste of time, then, isn't it.
Give it a few more days and if you still have no word, and there is no mention in the listing about the seller being away, you can always try phoning the seller if you are so inclined.
To the right of the Search bar you click the word Advanced. Then on the left side choose Find contact information. Fill in the info, and you'll get the seller's contact information, and he'll get a notice that you've requested it.
That way your call should come as no surprise. 
