I’m trying to add a second chime to my doorbell v1 and the + button disappears after I add the first chime. Any help would be great.
Welcome to the Forum, @patcheh! 
What did Support say when you contacted them? I use Video Doorbell v2 and don’t have a Video Doorbell (v1), so I don’t have specific suggestions for you, but I’m going to ask the Moderators to add a tag to your topic to see if that will improve visibility and get some other Video Doorbell (v1) users to respond.
Haven’t reached out yet, figured I see if it was something that I was missing first.
I think I’d try that, because I don’t have that particular product to test, and off the top of my head I’m not sure who I know in the Forum who uses the original Video Doorbell, so I don’t know who else to tag into this topic.
Thanks for taking the time to reply. I wish I had a quicker answer for you.