How can I tell who got the save the date email and who didn't. We have received some rsvp's but heard from other guests who didn't get the email. I confirmed the email addresses with them and they are correct but even re-sending the save the date didn't get through either. They all seem to use comcast.net. Is this a known problem? How do I know who got it and who didnt? This seemed to be a perfect and econonical way to announce our destination wedding but now I'm not sure!