Xfinity Now internet modem setup
It turns out you need to call the prepaid department to set up the modem. You can't do it by yourself through the Xfinity app. I was a regular Xfinity internet customer, and I wasn't able to switch to the Xfinity Now internet in my account. I called Xfinity to make the switch, and they cancelled my regular internet plan and signed me up for the Xfinity Now plan, which is a prepaid plan. As long as they cancel your regular internet, I think you can choose to subscribe the Xfinity Now plan on your own on their website. With the Xfinity Now modem, you can't customize your network credentials: you can only use the network name and password on the modem label. So far I am happy with my 100Mbps plan. It is cheap and straightforward. As a pay-as-you-go plan, it allows you to pause the service by not turning off the autopay. I like the flexibility very much.