I once saw a clever summary from R’ Arye Kaplan: A missioniary is like a telephone hotline. Push #1 for 1, Push #2 for 2. If there is nothing programmed for 9 and you push #9, they will just repeat the same thing over and over again. You’ve just got to think outside the box a bit!!
R’ Nissim from London once confronted the missionairy outside Yeshiva and spoke to him for about 1 1/2 hours – politely, and answering questions. He had a TNa”CH with him, and went through the Pesukim and proved the poor fellow wrong each time.
Once he pointed out – this is quite an important point – ???? does NOT neccesarily mean the Messiah – it means the Annointed One, and can refer to anyone from Ahron HaKohen to Dovid Hamelech. Anybody can be called the Annointed one of God without being the Messiah. He then proved this from many places, leaving most of the proofs the missionairy had worthless.