Ring Video Doorbell Pro - Diode

I purchased two Ring Video Doorbell Pro's. The first installed at the front door with no problem. The second at the backdoor would not stop ringing once connected. I have a digital door bell. After doing some research I found that this may be due to the fact I need to install a "diode". However none was included with either package. After speaking with Ring and Amazon they refuse to send me a diode.Is there a way/place to purchase the Ring Video Doorbell Pro diode?