I know you said you already complaint with Air Canada, but base on my own experience, when I log a complaint at
Air Canada Customer Relations, I also get some compensation. I best I have was 25,000 AEROPLAN or $300 off the future flight for a flight cancellation that delays my flight to HK for 3 days (yes, 3 days, don't ask me why). The next best one was another flight cancellation at YVR that I already got a hotel stay, dinner voucher (that was for all PAX) + actual dinner for being Elite (not sure if SE even more), but still got another 10,000 AEROPLAN miles or $150 off future flight after complaint. Both times, I have a very similar frustration like yours where AC GA just keep lying and kept us at the gate waiting and waiting. Another time, I did once email the AC President that time (this one is almost 8 years ago) and I got a 5000 AEROPLAN for just minor complain.
My suggestion is that if you haven't yet, do file a complaint at this site and see what you get. Do not shy to type an essay.... which is what I did every single time. Once the agent actually was too lazy to read and just call me and discuss (negotiate) on the phone with the compensation.
Congrats. I'm glad someone is able to recoup lost time and aggravation they cause. 3 days!!!!!!!!!!!! Thats astounding even by the Mariana Trench depths of this airline. WOW.
Thats a good tip on the essay too. I might just file one for the numerous screw ups they've done to me over the years. I missed my second childs birth because of their "service". Tried to get from Halifax to Providence. Showed up at the airport 2.5 hrs ahead of time and the Halifax to Toronto flight was badly oversold. Told the gate agent my situation (bear in mind I could rent a car and drive in 12hrs.). She booked me on a flight to Deer Lake NF then Toronto, then Providence. Long story short I arrive in Deer Lake at 11pm and the flight to Toronto was a 6am. Deer Lake isn't exactly a happening town and the airport is frankly deserted. It was probably -20 degrees out and as I slept on a hard plastic seat my son was born. At that time I could have killed that agent.