There's a reply function on the forum, use it or it will be hard to track who you are responding to. Regardless while the system is how it is, there is a penalty for leaving content without an abandon, and if people opt to take that penalty and leave, you are not entitled to that persons time, you can certainly argue that you should be and people should get their mentor status revoked for doing it, but that leaves the system open to abuse from the other end.