Unknown device connected

[Artbreak55]

I have a connected device in the Xfinity app called "Valued Customer" that is showing activity with an IP address that is not in my household.
I purchased a laptop from CDI through Comcast which has a different IP address and the app indicates "not connected", yet it is.
I'm not sure how to correct this, getting through to a real person rep with Xfinity is a challenge. Any idea how I remove the unknown connection? I have tried using "connect" in the app for the new laptop, but it just says device not connected.

[ComcastDena]

Thank you for reaching out! I know I would be concerned about a device on my network that I do not recognize. Here is a link: https://comca.st/3pDaOnA to see how to manage and remove registered devices. If you feel that someone is using your network you should change your password (learn how to with the link: https://comca.st/2ONzywA.) I would also suggest to report this to our Customer Security Assurance. You can contact CSA by calling CSA Toll-Free Number: 1-888-565-4329.

As far as the lap top that is not showing to be connected, have you tried to forget the network and then try to reconnect? Are you getting any errors other than 'non connected' in the app?