This is sick.
The guy/gal couldn't have got your email address from KMC, we don't give out email addresses. If they sent you an email from KMC, then the email would have specifically said the message was sent by a member from KMC.
It should be possible to find out the IP address of the person who sent you that email. If you can, then I might be able to link it to a member here.
But having said that, it is VERY likely that you know this person and that person is playing a very sick joke. I can't think of another reason why they would have your email address.