Of course the woman is being dishonest by withholding her name and phone#. She knows if she divulges that info that Maggie's family will be contacting her immediately, wanting Maggie back. She can't take that chance.
Of course they want her back, and because she knows who the cat belongs to she should give it back because it doesn't belong to her.
I bonded with my cats in the first hour of bringing them home, so like Maggie and her child i have a special relationship with my cats, so i'd move hell and high water to get my babies back regardless of the situation.
When i came out of a relationship when Rosie was under a year old she was my miracle because i was hurting at the time, but she made coming home a pleasure, so for all we know Maggie could have been this couples miracle also?