Question

How do i delete a family, i put them in twice by accident

Answer 1

Click on the [My account] button.  Then click on the [Remove] button next to the family to delete.

Answer 2

For 2 families in one tree:

1) you need to link both families by highest  common member by changing parrents (chose from tree)

2) delete duplicated familiy (the rest)

For displayed memeber(s) as duplicate in 2 families you can't do nothing. It's natural to being displayed twice.