don't touch my baby

Me and my ex husband have a 2 year old baby girl together. And my ex husband has this new girlfriend and she's always taking pictures with my baby and acting like she's hers. I told my husband to tell her to stop but he just got mad at me. I feel like she's trying to replace me as my babies mother. And as if I already didn't hate her enough, she spanked MY child. She crossed the line! Nobody lays a finger on my baby. What would you ladies do? I feel like calling the police on her. Either that or beat her ass
And for those who said be thankful for my babies "stepmom" No I won't. Everything was fine until she came into our lives. She's cause so much trouble. She's cussed at me on social media because I politely asked her to take a picture of her and my child down. And she blew up on me. I know she and my ex husband are talking bad about me to my baby. My family can't stand her either. She is bad news so no,I won't be thankful for her. I'll be thankful when she leaves our life.