I have cancelled my koodo account today but I can still see details on self serve. My outgoing calls are stopped. But I didn't get any message that your account is cancelled and you will not get any new bill.
You will see your account on self service for about 90 days. That has happened to me,too.
If you have received a final bill and your service is stopped, I'm sure it is cancelled.
But you can contact Koodo to make sure it is canceled. You might have to press "0" a few times to speak with a rep when you call them.