I still can't find her
That's a bug I recently discovered, I'm sorry it happened to you.
It happens when you do some activity while the quest "Soul in the shopping mall" is active, for example: Going to the coffee shop and ordering something.
This bug has already been fixed in v0.1.8.
The game skips the end of the quest, completes it and then it doesn't re-activate the girls.
This bug won't happen if you go straight to the shopping mall to complete the quest.
Again, I apologize for this bug.