The problem is your tracking yourselves, not the account. if I were next door and had your details I could just connect up and use your account. It wouldn't go through your system and only the bills would show I'm doing it. How do I get this information? easy, i hack your mail box witha spyware keystroke program, I already had access to your system and once I have your e-mail account details I just make sure a copy of all your e-mails also come to my email account, so if you change details the verification email also comes to me with all your new passwords. i would always use an obscure email account to send details to, or a work one away from the system for that very reason. It only takes an e-mail from videotron asking you to log on to verify details, if thats a jacked site when you go to log on the information you see as ****** will apear as the exact keystrokes you used, then they forward you to a standard "page not available, please try again" site and you log in the usual way from a bookmarked page, but now they have all the details they need, they whip into the account and add themselves to your account, any information you recieve they also now recieve, eventually they have enough details to do what they like. Usually you need to be targeted for this to happen or have your wireless account on 24/7, that makes you an easy target as they see a signal over a few days and they know they have all night to play, most hackers work in the small hours or when your downloading so you don't realise they have sent spyware and are looking around your system files as the hard drive light is flashing away, (if it did this an night you would be pretty quick to notice). My only advice is ensure your router is off when not in use, and if they still have access to your account, time to shut it down, reopen a new account with different numbers and protect the system (add an 'i' in front of your MAC,
sorry I couldn't resist) this was one of the reasons I made the swap to apple, I have never bothered with anti-virus's for 7 years now.
I am in a lot of doubt they go through your router, I think they have your connection details. videotron should offer some protection from this happening if you can't stop it by turning your router off, if they don't then they have no reason to keep your details confidential. Time to pay for a better service
or at the very least look around for someone else.