I have zero sympathy for Natasha (SPOILERS)
As harsh as this may sound, I didn't feel one bit sorry for her in the film. I know she went through the pain of her parents just abandoning her, and her death was due to their negligence. However, it doesn't justify taking someone else's mother the way she did and leaving another little girl motherless, or the way she was going to drown Ceci right in front of Dahlia unless Dahlia did as Natasha wanted.
Natasha went through something that no little girl should have to go through, but when she knowingly put another girl through worse, it's hard to feel any sympathy for her. She may have been lonely and in need of a mother figure, but it was no excuse for blackmailing Dahlia into drowning herself and leaving her daughter, when she knew how close they were.