Cancel your direct debit and theyll soon send you a letter with a phone number to ring, and then tell them you dont watch BBC or anything that relates to them , theyll give you abit of a chat about if you get caught watching it blah blah blah, theyll then take you off their list. Thats what i did.
Write and email them telling them you no longer want a licence for the property. If it is a house you live in; Ignore all threatening letters and let no one into your house without a warrant and an attending police officer. If the BBC Stasi come to your door and you have a drive, tell them they are trespassing. If there is no drive, close the door on them. Keep a record of their letters, visits etc. Write to the BBC and keep a copy. Inform them that they are harassing you.
Worth noting that a warrant from a Justice of the Peace, which they usually procure, is worthless … … it has to be signed by a magistrate to be legal and that’s much more difficult to get.