The title of the drama has nothing to do with the story they tell, it's just that she's Cinderella because she's poor, has personal problems, her ex is rich and handsome and her ex-boyfriend's mother is "bad", from there on there's nothing that involves the concept of Cinderella. But the story becomes so repetitive episode after episode, that it becomes long, tedious and boring.
I liked the story that developed with the secondary couple more, that I even preferred that a drama was made about them.

(bonus point: yeonjun OTS)