You had a free hooker slot when recruiting her? For 100k you get the girl but no free slot (in contrast to the real money girls who are recruited with an additional slot).

In general a dialog is popping up when you recruit without free slot. There you can kick some other girl for her, send her to spare part graveyard or you get 24 hours when you close dialog (symbol at the right side),

Since you said she is gone i would advice you to check your graveyard for 10 star hoes according to her ethnic ...

If you find her i will call you gravedigger in the future ;-)