I'm being asked to return a TV box; didn't get one to begin with

Last month I cancelled my Xfinity internet plan. I keep getting calls and texts asking me to return equipment. I had my own modem/router. When I call Customer Service, they state that I have a TV box for streaming services. I don't have one and don't remember ever getting one.

I asked for details, they said it's a X1-pro connected to my TV, black, and about 9inx9in in size. I never got anything like that when I became an Xfinity customer. Online searches tell me to check whether I have Xfinity streaming services by using an Xfinity remote to look - I have no Xfinity remote.

What do I do? I don't want to be charged for failing to return an item I didn't receive.