You can use Burner App to call Canada Immigration from within US or other country where the App is available

I have tried it from my US phone number and it works like a charm. It assigns a Canadian number to your App so that you can connect to Canada Immigration toll free number using your US phone number or other country’s phone number where the Burner App is available.

They give you free talk time of few minites, after which it is $4.99 / month