Xfinity asking me to return equipment that I never had

Hello, I keep receiving texts/emails from Xfinity/Comcast to return equipment that I never had (cable box). When I opened my account, I performed a self-install for Internet and that's it. I never even had cable tv service. I used my own cable modem and router that I purchased from a big box store. Why do I keep getting these notifications? Is this a Xfinity/Comcast scam for cancelling the service? I see a lot these exact same situations posted here and on the Internet. Please, I do not want to be charged for something that I never had. Thank you.