If you don't see emails in your MailChimp list, there's a high probability that it's related to one of the following reasons:
Are you sure that people are signed up? As a reminder, emails input in the website preview are not synced.
Check if your list has a required field in it (such as the first name). In that case, please make sure your have a Wisepops field matching this required field; or change your MailChimp list settings so that it has no required field.
MailChimp will automatically filter out emails that are already in your MailChimp list. So make sure to test your pop-up with an email that's not already in your list otherwise it will not be synchronized.