The solution still stands. In a non-threatening way you make it known you know an activity or accusation is unfounded and, if pressed, you may take further acti

The solution still stands. In a non-threatening way you make it known you know an activity or accusation is unfounded and, if pressed, you may take further action. And you do this in writing, clearly stating it is for documentation purposes. Nothing will make HR/legal stop in their tracks faster (unless you really are in the wrong)