If you really are, my recommendation is to get stern with your responses. I got them to stop for a little while by just asking them to stop, and then to stop en

If you really are, my recommendation is to get stern with your responses. I got them to stop for a little while by just asking them to stop, and then to stop entirely by asking again while mentioning who I sent my previous request to. Like "Hi John, please stop contacting me", and then a few months later like "Hi Steve, a few months ago I asked John Doe (johndoe@) to stop contacting me". The second step seems to have been the trick.