Or tell them you got free internet and cable for life from one of their competitors (and if they ask how you got it, tell them you changed jobs and you now work for them). It would be impossible for them to match that offer, so they'll just leave you alone. If they do match that offer, it's still a win!
It has already worked for me more than once (unfortunately, nobody ever tried to offer me free service).
It has already worked for me more than once (unfortunately, nobody ever tried to offer me free service).