Hello @DebraG71 ,
If your contact is unable to confirm their resubscription via the email, and unable to opt back in via a sign-up form, I'd recommend going with our manual override option. To do this, get an email directly from the contact explicitly stating they wish to resubscribe. Then reach out to our Review team, and they'll be able to assist from there.
Since the nature of unsubscribing has several legal and compliance-related elements to it, we need to have a paper trail to ensure they're being resubscribed with permission.