Unable to pair zwave switch

Hate to jump in late, but your switch was probably fine. There is a thread where people are seeing this issue:

I had the same issue with some non GE stuff. I just toggled it at the switches and it cleared the unavailable thing in the app.

I know from personal experience I had one HE!! of a time getting one of mine to reconnect. I had to call support and have them walk me through it. It was for a different issue but they had me remove / exclude it and we had a hard time getting it back on.

I’m sure you have been here. This is where I started when I was trying to get mine to work.

https://support.smartthings.com/hc/en-us/articles/200879274-How-to-connect-GE-Z-Wave-switches-and-dimmers

Hope you get it back up and working.