If you have one of those telephones that shows the number and you don't recognise it just ignore it - that's what I do, if it happens to be something important whoever it is will leave a message, and you can contact them if you like, I get a lot of calls which say International which I also ignore - those are usully con men from abroad. Those calls which get through if you aswer them, inform them that you are on the TPS list and ask them to remove them from their call list, they are obliged to do this.