If you could please email us the email addresses you are having trouble receiving from at social_support(at)constantcontact(dot)com, we can take a further look and troubleshoot for you. In the meantime, if it is a Gmail email address, the email will be in your Promotions folder, so I would suggest to look there! You can click and drag the email from the Promotions folder to the Primary folder, and it will go there going forward.
You could also do a Spam Check on your email to be sure there isn't any links or content causing the email to not be delivered. You could also schedule the email out as a live send to an email list with the two of you on it. This way, we can see the reporting of the email to see if it is delivering, or being bounced by your Internet Service Provider. Once we get your email of the addresses, I can search them and be sure they aren't blocked in any way in our system!