In my personal life, I've sometimes had to cut off ties with people or at least limit how I interact with them. Sometimes this has been over disagreements over basic facts or behaviour. On a few occasions, I've told a person that eventually I'll be vindicated as I did so. It's easy, when you're eventually proven right to say "I told you so." While technically true, it's better to soften the blow with "I did try to warn you." Better for you (because you're not clinging onto being right for its own sake) and better for the other person because it makes reconciliation easier.