Extra Equipment - Plan Change

I recently changed my plan to just lower my internet speeds since I was paying way too much for internet speeds I don't even use. However, when I changed the plan (I selected that I wanted no modem/router, TV stayed the same), Xfinity says they are sending me a package. I got confused because I do not need anything extra from the old plan to the new one, so I am unsure what they are sending me. If it's a tv box, I already have one, so I would like to somehow cancel the package. How do I go about doing this?