First off, I am SO terribly sorry for what you had to endure! This is horrible!!!!

I do have a slightly different take on it, however, and please excuse my straight forward manner of talking.... I say this with compassion.

So my take is that his mother may have thought she was helping you by telling her son she had called the police. My guess is that your text must have scared her enough to call the police on him. She probably also got really scared when the phone was grabbed from you and she lost contact with you. She probably also thought it would scare him to tell him that the police were contacted.

So another angle is: it was your ex who hit and beat you, not his mother. I think your anger is misdirected here.

He's the one to be irate with... he's the one responsible for beating you. He's the one who deserves all your rage, anger and disgust. His mother is not responsible for any of it. For all you know, what she told her son may have even scared him from doing worse and may have even saved you!!!

Just another angle to consider.... again, I am so terribly sorry. I am sure you've been through the wringer because of this.... HUGS.

If you have not already, I would seek the assistance of a counselor to help you to manage your anger and feelings over this horrendous incident. I can't imagine what you must be feeling about it so some professional support around this would really help.