No action is needed on this anymore. After hours of chats with support and numerous exchanges with our new provider and their communications with email@example.com, we've moved on and abandoned our efforts. Essentially - we cannot port our number out of TextNow.
Note: the TextNow porting team does not have a phone number and will only communicate through the email. If your new carrier is trying to resolve an issue with TextNow porting team, they will need to communicate only through that email. Isn't that interesting that a phone company does not have a phone number for customers to call.