If a seller does not specifically say that they ship to Canada , and does not give a specific shipping cost and service, always ASK BEFORE BIDDING.
Often the seller just did not think to extend their offers to their northern neighbours.
But if you get no answer, or the answer is vague, or you are refused, move on. Another, more helpful seller will be along in a moment.
In your specific case, if the seller offers a Mutual Cancellation, agree. This will release you from any obligations you may have entered by making your offer.
