I use several tactics that look to work getting rid of these calls. Once you learn to just use them they work most of the time.
* Computer virus with pc. "Sorry you must have the wrong house as I do not have any pc or mobile phone, thank you for calling" then put the phone down.
* Can I fit new windows / guttering / gardening etc.. "Sorry I am renting the house", they just give up and go away.
* You have won xxxxxx on lottery, bingo etc. "Sorry I do not gamble or drink so you must have the wrong house"