What steps should I take to make sure that my child stays with me?

He put his hands and foot on me and I sent him back to live with his mother. He stopped helping with the baby who is 9 months old. His mother swears my child is hers and I know she's the one behind this filing for custody. Everyone who knows me know that I put my daughter first and take great care of her. I saw online where he files for custody and paternity. Then his sister text me saying that I can’t pay my rent so its all a plot because he decided to stop put his part towards the rent. They thought that I would become homeless so he can get my baby. They are so bitter because I refuse to stay with a man that put his hands on me.