My mother lived in Pointe Claire and received internet service through Videotron, a Quebec ISP. To cancel you have to call 1-888-433-6876 and have your name on the service. In our case my mother had passed, so a phone call from her would be supernatural.
I’d maintained her service, so I had her user name/password. Videotron’s web site doesn’t support canceling their service, but they do support adding a name to the service. I did that to add my name and contact information; then I was able to call and cancel.
Cancellation went quickly once I mentioned she’d died. They need her cable modem and power supply back within 1 week or they’ll charge us $69, when it’s returned we have to provide her account number.