People have been asking this question for years on this forum. Unfortunately Google refuses to sell any parts for any of their cameras. I don't know what Google treats its customer base so poorly. The only time they will help you is if your camera is still within the 1year warranty.
You can try opening an official support ticket with Goggle if you want to give it try and see what they say.
https://support.google.com/googlenest/gethelp
