Doorbell registered to another user

Please I just bought a ring doorbell with back transfer as payment. I tried installing it but it says it’s registered to someone else. Sent the person a Facebook message who has now refused to reply my messages . What do I do . It has all the boxes, stickers, screws

Thanks . I just took a gamble because she sounded genuine and it came with all the stickers, boxes, screws and screwdriver so I believed it to be genuine