I'm frustrated. I was supposed to fly YXU - YYZ - ORD - ATL. Unnecessarily complex routing that would make sense just a week ago. But the problem is that AC8256 won't catch AC8849 at YYZ. So I'd have to use AC8252 at 05:10. I wasn't willing to do that on Sunday. So, just I was departing to the airport, I received a text saying AC505 to ORD was canceled. Then I received a text with a new routing via YOW and YUL, arriving to ATL around midnight today. Unacceptable. After spending the whole cab ride to YXU on hold, I asked the folks at YXU what could be done. Yesterday, nothing. However, 8252 for today was Y9 and 8949 was Y1. So I got rebooked to today. I got up at an ungodly hour to be of 8252...just to be waiting at the gate for 8949 that is already late and we still don't have a crew. So our expected departure at 10:30 won't happen. And my calendary for the afternoon is full...