Ring Doorbell, cell phone change

Hi, first of all sorry for my englisch. Im from Germany. My Problem: I got a ring doorbell and it was registered on my account. Now i got a new cell phone. I automaticly transfered the app to my new phone. I logged me in and could see that my account is there. So i deletet the doorbell from my old cell phone. I did not know that its not automaticly in the app from my new phone. Now i cant get the doorbell on my new phone app or on the old one. The only thing i can do is add a new one. But when i scan the qr code it says that it already belongs to someone. How can i get the doorbell back to my old or new phone. I realy hope u can understand what i mean and help me. Thx Minime