Only the seller knows why they cancelled your bid. Was it a US only item? If so, maybe the seller realized you are in Canada and that's why they cancelled and blocked you (I'm only guessing. That may not be it at all).
Since you did not win the item, you cannot leave feedback.
You are not out any money on the transaction and not knowing specifically why the seller blocked you, I do not see anything dishonest on the part of the seller. If you had won, paid and either got nothing or something totally different, then that would have been dishonest.
Non paying buyers deserve unpaid item strikes.