Emails in payment portals aren't subscribers in Mailchimp?

[HunterTaylor]

Hi,

I have a mailchimp account but some of my mailchimp journeys aren't working because it is removing the emails that were put in when filling our the payment portal and putting them up as non subscribers, which doesn't let them finish the custom journey (according to MailChimp customer service) I've made for my business.

Can anyone tell me if this is true or if there is some sort of troubleshooting that i'd need to do to make sure my mailchimp journeys complete so I can take advantage of my journey and market more effectively.