Eupgrade Issue - Am I Wrong?

I recently booked 2 flights YYZ to GND. I've been super elite for a number of years now and have never used any of my Eupgrades because it always seemed like a gamble whether or not I would actually get the upgrade. This time I looked to see if I could use them and it turns out it was a gamble and I rolled snakeyes.

When booking, all flights showed waitlisted except for one flight which showed upgrade availability with a green checkmark. I booked that flight and immediately applied the eupgrades but it marked it as waitlisted. I searched for the flight again and on the AC booking system it still showed the green checkmark for eupgrade available.

I called the concierge who saw it was available but couldn't tell me why I was waitlisted. He said it should have instantly upgraded me. He said there wasn't anything he could do but said to call in 48hrs before the flight and speak with the team at the airport who could give me the upgrade. I called 48hrs before the flight and they couldn't do anything but said to call 24hrs before the flight. I called 24hrs before and they said they couldn't do anything either even though it appeared to be an error in the booking system and that I would likely get the upgrade at the aiport.

In the end we didn't get the upgrade, so I ended up paying more for a latitude fare than I would have had I just paid for a base fare because that's the fare that said had Eupgrade availability.

I'm disappointed and frustrated with this situation and also that years of super elite and loyalty to air Canada didn't carry any weight. We ended up having a bad flight (screen wasn't working and my seat felt broken and I was sitting on an angle thr whole flight) and I spend the time wondering why I even care about super elite and loyalty to air Canada.

Was this an error? Do I not understand how Eupgrades work? Am I just being a princess?