I want to cancel my Fido service for that I need to make a call from my Fido number and request it. But I'm outside of Canada and for some reason my SIM card doesn't work anymore! Whenever I put it on the phone, I have no service. The SIM card of my homeland country works, so that's not a problem with my phone. It's something wrong with Fido SIM card.
I'm not planing to go to Canada any time soon. and it's not even possible now. How can I cancel my service in other ways?!
It could be that Fido roam is not working the location where you are.
Only a Fido representative can cancel a line, you would need to contact customer service to have the cancellation process.
See here for the many different ways to reach out to customer service even from outside of the country.