Kendra said her dad is the boss at a place she calls the Abacus. An internet search on Rosa's phone for that name turns up --
Hint 2
-- nothing. You need more information, and you'll find it nearby, outside the house.
Hint 3
In the mailbox, there's a soggy letter with about half of a return address -- it comes from the Wired A something. Could that be the other half of the Abacus's name?
Hint 4
Do a search for "Wired Abacus" to get the address.