Two months later, still no progress. Except for WestJet getting back saying that they are swamped with requests and they deal with them with delay.
So, I am still where I was... being a hostage: WestJet is unable to give me confirmation that their flight was canceled "due to contractual obligations with our third-party vendors", because my ticket was issued by Delta.
So... West Jet sends me to Delta, but Delta says they are "unable to determine the reason for cancellation since they only have limited access". Delta recommended that I ask for this confirmation from the airline who operated my flight (West Jet).
My insurance would be happy to pay for my expenses but needs a confirmation that the flight was canceled. And nobody in this world seems to be able to issue a simple confirmation like this. I never received any message on e-mail from West Jet that the flight was canceled. I will do anything I can to avoid WestJet in the future.
When I see the wait times with DOT or CTA, I am losing my hopes this may be resolved before 2027.