Hey neighbors! It sounds like you are needing to complete the change of ownership process, which can be initiated by simply starting a setup in your Ring app. During your attempted setup, an automatic email was generated to the previous owner of the device instructing them to remove that device if they are no longer the owner.
While this email delivery is immediate, it can take previous owners some time before removing from their account. If it has been more than 72 hours since your first attempted setup, please contact deviceowner@ring.com for further assistance. I hope this helps! 