They said:
Thanks for your message!

It's not currently possible to reset the game, but you can evict a family once per game or wait until your current family members pass away!

Then sent a link to help center.

I had a problem with marriage and family tree going wonky. I.e not showing new people just stuck on one member that has already passed away, marriage says yes on one no on the other no matter what.
I had a member Lilesse who the game is stuck on even though she's passed away. Even announcing she's been married instead of the new adoption.