That's why they have the link. It redirects you to call them or use live chat to do it. Its not really silly unless you like someone going into your account and changing your plans without you knowing. Safest and best way is to contact Rogers via Live Chat or phone and change it like that.
I do miss changing plans online but a lot had problems with people logging in and changing it without the account holder knowing.
Why doesn't Rogers allow changes to packages (e.g., Internet, TV channels) as a self-service function online? Customers are required to call or initiate a chat session. I find this terribly inconvenient. Perhaps a fear that people will start cancelling too many things if they make it that easy.
They used to have this a few years ago. Its not really the fear of people cancelling things but more of security reasons i find. Not all service providers allow their customers to change plans / add ons or cable packages online instead they have the customers contact them to do it.