The solution is a list of Canadian roaming numbers. They don't work in the US, so it's not a solution to US roaming.My phone is Volte compatible. My solution ended up being using a VoIP calling app, as you mention, to call myself and access voicemail...
Thanks @softech I found the numbers list but it's just Canadian access. I'll try that # next time. This time, I solved it by installing a calling app, calling my number, then accessing VM.
