My 'mum' is a bitch!

PRETTY LONG BUT PLEASE READ AND REPLY!!
I disowned my biological mother years ago because she seriously is an awful mother! 
When we was younger she left our dad and married a horrible man. He repeatedly sexually abused my sister for years, he beat us, he starved us.. He was the devil! My 'mother' turned a blind eye and let him do it. Eventually my sister had the courage to go to the police and saved us all and he was put in prison. We all went into care and our lives changed for the better. My foster parents decided to adopt me a couple of years later. 
Anyway fast forward to 6 years ago. I had my first child and I gave my biological mother a chance to be a grandma. She literally threw it back in my face. Making promises to my child then breaking them. Not turning up to contact. Filling our heads wit lies and all sorts of other stuff. I then disowned her. Then I had another child and she has seen him once and not bothered again since. That doesn't bother me she made her bed. 
My sister has not long had her first child so she decided to give her a chance aswell. Not kidding she turned up absolutely filthy. I've seen homeless people a lot cleaner than she was it was absolutely appalling!! I got home and i rang social services, it's pretty clear she's not looking after herself and her husband isn't looking after her either. (She has disabilities) so I expressed my concern to them, o also rang her doctors so they can watch her, RSPCA because she has animals and if she's not being looked after those animals sure as hell arnt either, environmental health so they can check her house out and a few other places. Anyway i shouldn't even be bothered she's never cared about us. I rang and told her what I had done and I got all sorts of abuse from both her and her husband because apparently it's not my business. Well yes it is she's my mother unfortunately. 
Apparently she's going to report me because I don't look after my kids.. I do and if she does they will see my kids are looked after. 
My question is, am I in the wrong for looking out for her? I see it as just because she never looked after us or helped us when we needed it I don't need to be bitter about it and end up like her.