Not enough detail here to determine fault
Yours.
it is the person coming out of the parking space
The vehicle exiting the parking space that did not yield to oncoming traffic.
It is your fault.
it is both of their faults because the person who was backing up should have look more carefully and the the other car should check where they are going
both of you for not looking back
Backing up--it is your fault.
My fault
I beleive, whoever's car is moving (wheel-wise), is at fault.
Depends on the jurisdiction, but typically, two vehicles backing up is a 50/50.
The car pulling from the parking space is at fault
the person pulling out