"But on Sunday night I received a message from someone via Mundia about information in one of my trees. The sender not only knew my name but where I lived. What on earth do I have to do to make my tree non searchable on this duplicate site?"
What did they find - your tree or your name in someone else's tree? Where did they search - your tree or some web search? You mentioned "one of your trees" in another post - did Ancestry supposedly fix all of them? Why aren't you going back to Ancestry to make them accountable for what they told you they did?