These creeps are everywhere; you cannot get rid of them.  I once in desperation said:  "I have got my own religion, thank you, I am a Muslim"  thinking they will p... off.  Not such a luck, they decided they really have to save me LOL.  Now I have a sticker saying NO RELIGIOUS SECTS and the official DO NOT KNOCK sticker, and the moment they knock , I shriek at them pointing at the stickers and slam the door.  So the ordinary pimply youth do not come anymore; now I get the very serious elders in threes...................  Last time they came, I told them that as it is now criminal offence to knock on doors with the DO NOT KNOCK sticker, I will report them and have them charged with trespass; that was before Xmas and so far so good  🙂