I participated in their signature campaign a while ago (see link in my signature) - when I signed up with them their preferred email was gmail and there was an expectation that you provide a phone number as well as your gmail details. You should be receiving regular emails from them which have details of how to contact them.
Have you tried clicking the "reply" button in any of your emails from them?
Be absolutely certain you want to wield the "scam accusation" hammer lest it fall on you.