Ring door not showing on account after installing on app on a new device

A family member who isn’t very tech savvy has a ring doorbell which was registered to her account and all was working fine. She changed her phone device and downloaded the ring app to the new device and logged in but the doorbell was not showing. We have tried re-adding the doorbell by scanning the QR code, but we get a message that says the doorbell is registered to another account and to click here to ask the owner to unregister the doorbell. I don’t know who the email goes to as it was registered to her account but she isn’t receiving the email. What are we doing wrong or what has gone wrong? I would have thought that the device would have still been registered to the account when we resigned into the ring app on the new phone device, but it’s not. The phone is a Samsung and so was the old phone. Thanks in advance for any help.