Transfer of ownership from a deceased relative

Hey My Grandfather passed away eariler this year. We're in the process of selling his house, but we decided to keep the Ring Door bell and chime. However we're unable to transfer the ownership of the device from his account to mine. I know his username and password however the 2 phase authentication is requesting that I enter a code sent to his email I cannot access the email as the account no longer exists (It's an @eircom.net email, Eircom shutdown all the old free email addresses last year) I have no way to remove the device from his account. Any idea what to do here? (It seems very difficult to get in contact with Ring Support) Thanks G.