Hey Mark - Matt from GitHub here. I'm sorry that's happened to you! The good news is that you have some options to ensure that your publicly-facing information on GitHub is used for the purposes you intend.
Have a look over the updated privacy details at https://help.github.com/articles/github-privacy-statement/#p.... In particular, we ask any third-party groups to not use public information for commercial purposes if the user has made their email address public only for attribution and identification.
If you feel like this solicitation is out of bounds, then give our support team a holler (support@github.com) and we'll see what we can do to help.