You may have been Blocked by sellers (not necessarily eBay) for having Unpaid Item Strikes, because you bid on a item that the seller does not ship to Canada, or because you do not have an active Paypal account.
The Strikes will age out after a year.
You might be able to Contact the seller and ask her to allow you to bid.
Open a PP account and (this is important) back it with a credit card. This gives you the fastest service and a second level of Buyer Protection.
