AWS Cognito and SES not sending emails TO formerly unverified address

A user in my AWS Cognito user pool created their account within Cognito BEFORE they SMS verified their own email address (Yahoo, if it matters). They never received a confirmation email, and even after they verified their own email they aren't receiving any mail from these AWS services. I have tried to delete and re-create their account via Cognito many times but they appear to be black-listed from receiving emails from AWS services. Any advise or direction is appreciated.