Hi @Rochelle_Barlow and welcome to the Forum! 
It is possible that the referred member might have been removed from one team, but not from the entire Organization. Please, have a look at the following article to learn how to fully remove someone from your Organization.
If this is not the case, I would suggest you to reach out to our support team who will be able to take a closer look into your account and let you know exactly what has happened.
Hope this helps! Please let me know if there is anything else I can help you with!