Access not authorized for account

I started service yesterday and picked up my router, but I'm unable to access my account. The Xfinity app keeps saying "access not authorized."

Although chat support activated the equipment, the problem persists on both my phone and laptop, even in incognito tabs.

A phone agent mentioned there are two accounts, one inactive, but didn't provide a fix and tried to sell me more services. How can we get this resolved so I can fully manage my account?