Unsolicited trade calls to the door not taking no for an answer

[Robster59]

Our council has made stickers available for people to put in their window. I have to say it's virtually eliminated cold-callers to our house which is a real benefit as I work from home.
I did have some Jehovah's Witnesses knock so I pointed at the sign. They tried to say that they weren't selling anything but I told them they were selling religion and to go away.