I actually went through this exact situation with Air Canada last year, so I can share how it worked for me. My original flight from Toronto to Vancouver was canceled the night before due to operational issues. At first, I was pretty stressed because I had meetings scheduled the following morning. I got the email saying I could either rebook or request a refund/credit, but the online portal was moving slow and kept glitching. Instead of waiting, I just called (877)-764-3622, which turned out to be the fastest way to deal with it.
The rep was super clear and walked me through the process. First, she checked if there were alternate flights I could switch to for free (which is always the first option they offer). Since nothing worked with my schedule, she explained I could choose between a full refund back to my card or a travel credit. I went with the credit because I already knew I’d be flying again soon. Within a couple of days, the credit showed up in my account and I used it for a trip a month later without any issues.
So yes—you do have options, and calling (877)-764-3622 really simplified everything for me.