After you were logged in, it used to be under Your Aeroplan -> Air Canada Top Tier and then there was a link to priority contacts.
Unfortunately, it appears that they have removed the link for priority contacts, as well as the link for the top tier offers for other partners. I don't have the information on me right now, maybe someone else can send you a PM. Are you looking for the Aeroplan special number, or the Air Canada special number?