Phone number's in the app. Go to the "Aeroplan" tab at bottom right, then tap the image of your membership card, priority contact number should be at the bottom of the page under the QR code and your account number.
As for the eUpgrade, it really depends what route you were flying and when. As a 35K you'll often have trouble clearing on routes like YUL-YYZ. When you say "8 open seats" do you mean you saw 8 unoccupied seats on the website seat map, or an ExpertFlyer search showed the flight as J8, or that your flight left with most of the Business cabin empty?
Also worth noting that AC's upgrade policy is very different than AA/DL/UA. They won't just keep upgrading Elites of any tier until the J cabin is full, if they think the flight is likely to sell then they'll keep seats available for purchase (but not upgrade) right up until departure, at which point a 35K who's been waitlisted for a week might get bumped down the gate-upgrade list by a SEMM who requests the night before.