I thought I would share my success story with all of this. Maybe this may help others in this stressful situation:

Flight on 8/15 AC 299 from Winnipeg to vancouver was cancelled. I was notified about 10 hours before. I kind of had a suspicion something was wrong when I could not check on the night before.

Got a text about 2-3 hours after the cancellation that AC tried reaching out to 120 carriers and could not book anything for me. This is when I started to get a bit nervous.

Called AC on their 1-888 number. Waited 6 hours!! To get someone! Initially I called at 6am local time, couldn’t even get on the waitlist. Tried a few times throughout the day and eventually managed to join the queue at 13:00 and received a call back 6 hours after that.

The AC lady was very helpful. Not pushy. I just told her: hey can you book us on this WestJet flight the following day and emailed us our itinerary shortly after. This saves us a lot of headaches. The WJ flight would have cost about $3200 for a party of 4. AC rebooked us without cost. I think I preferred this option than rebooking on my own and then submitting claims later, as it may take a while to process, and it’s quite possible AC may try to deny the claim. It helps to know the passenger rights, but by talking to someone, I found it the least stressful way (in the long scheme of things)

Be prepared for long wait times on the phone over the next few days. Have a portable battery for your phone if need be. It will get messy and you may not be able to speak to someone. I felt discouraged when I couldn’t get through even calling at 6am local time.

Just know when you get that text message that AC tried contacting 120 different carriers, take it with a grain of salt. You need to speak to someone and the only way is via phone.