I could be way off here but I am guessing that ebay is saying that you can't sell because your account is linked with this other sellers who apparently sold some fake items?
From what I understand they usually get that information if both users use the same computer at any time or the same ip or same address...etc... If that isn't the case, I'm not sure how they would come to that conclusion.
Since ebay customer service isn't helping, you could try writing to one the ebay Canada reps.
email is raphael@ebay.com