As well, the very password to access the modem settings has been changed. It used to be the standard admin / admin combo, but now I haven't a clue what it is. I've tried mixing and matching various usernames and passwords that I could remember, but none of them worked. Now here's the strange thing:
NVM. Figured it out. My Dad was instructed by someone on the phone from Bell to hit the reset button on the modem. Somewhere in between then and now, the username for the modem was set to the password for the internet connection, and the actual password was changed to a 26-character string, that I'm never going to remember.
Bah. At least it works.