Tivo and Cox

I have Tivo, I asked Cox to provide a tuner and cable card so that I would have service. They keep demanding that I have a contour box. I keep asking why the tuner and the cable card provide the service. They keep saying I have to have one and it has to be plugged in. The one they left here has not bee plugged in since the day they left it, and everything works fine. 

Why can't I get someone over there to understand that I don't need or want to pay for their box? I have my own. :(