We can argue your existance-we can even accept the premise that "you" do, in fact, exist. Mere existance, though, is not a basis for ownership-you cannot say that you own "yourself" merely because of existance, especially since "yourself," selfhood, and personhood remain completely undefined terms, and, as we've already demonstrated, you can lay no claim to ownership of your consciousness, which also, btw, remains undefined.
Did you make this argument?
If the answer is yes, then you exist and you own the product of your existence. If the answer is no, then who made the argument? Who is responsible for it?