Curious if you have any insights on recourse/compensation for the following:

My partner was flying AC to Paris yesterday from PIT-YYZ-CDG with confirmed boarding passes etc. There was a 3+ hour delay for the first leg due to covid staffing issues, so she asked if there were alternate options to get to Paris from the ticketing desk that evening as she was concerned about making the connection. They didn't find anything useful from PIT, but we had found some alternate options from YYZ so after this experience she left and headed back to the gate to try her chances of making the connection as the the outgoing flight was also delayed. Apparently, when she left the ticketing desk the agent cancelled the ticket without her permission or telling her because she was denied boarding at the gate and told her ticket was cancelled. She had a boarding pass from when she checked in, although it didn't matter. She was told to pick up her bags and leave the airport and had to wait 2 hours on hold to get through to a useful agent who could issue new tickets on AA for the following day. The agents at the airport were completely unhelpful and I am still shocked that her only option was leave the airport and call them for help.

Is she due any compensation for this 24+ hour delay to the arrival time? Air Canada really messed this up and the local agents at PIT clearly had no idea what they were doing.