Can't sign up for home phone?

I'm an Xfinity internet and cable customer and want to transfer my home phone number from Verizon to Xfinity. I have my own modem that has phone capability. When I log in to my account and try to change my plan, it only offers me mobile. When I go to the Xfinity Home Phone Services page and click Shop Home Phone, I get the same Add Mobile page. However, if I go to the Xfinity page and don't log on and act like I'm signing up for new service to a neighbor's address who isn't on Xfinity, I can choose Home Phone. Why can't I add Home Phone to my plan?