Norine Simard, I'm not Canadian but I can definitely help you. I'm confident for this job as I've already fixed similar bugs in past.
You should not suppose to upgrade website to new version until you take backup of your website due to that reason something went wrong while upgrade and site went down.
Now I have to review code of your website and then I can find what was the issue and how quickly I can make your website live.
If you have any query feel free to ask me in message box.
Thank you,
Manish Narola