It's your life, I can't tell you what to do. But reading through this and having followed your saga to date, it's clear to me that you are making one fatal mistake: You are meeting them on their own ground. The narrative you provide suggests you have been put into defensive mode and are left with nothing to do but argue each point they bring up, whereupon they have an answer all ready for you. That is what these people are trained to do. Once they go home, you are left to wonder what you could have said.
You want to fight fire with fire and turn this around. Do not let them ask the questions (i.e., conduct a study). All you need are three good topics and the support arguments and you can rip them a new one. And all of that info is here on the forum. So, it would appear that something is in the way of your being proactive on this. When you figure out what it is, you will be in better shape to fight them off.
Think about this: They are threatening to take over your family. They are on the verge of capturing your wife, mentally and emotionally, and turning her into a slave. And they'll take you captive too, if you left them - although they don't much care if you come along or not.