None of your business and makes you look bad.
Not your place to tell someone what to think of another.
it's harassment they steal one of your proper right without knowing :)
It can be considered slander if the information you pass along is derogatory. If that happens, you have some legal issues looking at you.
Based upon "what she did to you", yes, that would be slander. By the way, with friends like you, who needs enemies?