Someone who is a Policeman or Lawyer please help!!!!!?

Why is it that for the past 2.5yrs I have been stalked harassed, abused, assaulted, threatened on an average of once a week, that i have reported all these things & the police do NOTHING. I had to myself take out intervention orders on these 2 ppl (mother & a daughter) for myself & my kids. Only to get on that can only prevent them from talking to us. I have had them extended twice now so obviously the court sees they are in the wrong. But my kids are highly effected by it all, they witnessed the assault when the were only 4 & 6 & have witnessed all other abuse etc too. They fear them & a traumatised sometimes too scared for school as the daughter has a child in my sons class so this makes it hard because they are forever hanging around the classroom which makes my son very uncomfortable. They continue to intimidate which all they have to do is be around for that to happen, the school are hopeless & even when things were set in place to stop them they just disregarded them anyway & the school are too scared to stop them also. 3 mths ago my husband had enough when he witnessed my daughter have a nervous breakdown at school just from them being there. he decided to have a chat with the Grandmother in the main st. it was of course quite heated & he did use the occassional swear word, they also abused him back even though he tried walking away 3 times, the grandmother was trying to get him to hit her by asking him to do it, the daughter was also yelling abuse. she followed him to his ute & pushed him in the back almost making him hit the ground, he swung around with his hand, expecting another hit from her as she was the one who assaulted me, & she was right behind him so the tip of his fingers slightly brushed her hair. she grabbed at her face & pretended to fall to the ground, she is saying that he hit her in the face. To make matters worse her daughter & 2 other ppl are also saying hes done it, of course none of them are saying that my husband was pushed & abused also. A witness across the street saw the push, she went to the police & told them my husband was pushed but the police arent even going to use her statment in court, yet they are taking the word of 3 well known criminals & drug dealers. I dont know how clear I am being in this as there is soooo much more to the events over the past 2.5yrs. I just want to know what I can do, where do we stand legally. He is being charged with offensive behaviour in public which is something that they do an a regualr basis & never get charged so why is it that my husband was defending his children the police arrest him for it. I have nowhere left to turn, they have destroyed every part of our lives, we have none of our friendships we had before all this, my own father has taken their side, the police wont listen, my kids cant live a fully normal life as we live ina tiny town there is no way of avoiding them which means they cant atend sports, dances etc. And as for my marriage well, i dont know how much longer we will be together, too much stress, we dont blame each other for all this but we always seem to end up arguing like we do. Someone who knows the law is a lawyer or policeman please help me. I live in Australia