8 years of hell with narc ex. Where do I go from here? Please, I need help

This is going to be a long one, I appologise. But are there any mums on here who have experience in dealing with a narc x and how to go through the Aus court system to make him stop? Bit of background:

My ex and I share 1 child who is nearly 8. I left him due to DV (verbal, emotional and financial abuse) when our son was 1. The last near 8 years has been absolute HELL for me. At first when we first separated he was an absent father. Constantly cancelling his fortnightly visitation because he had "band practice" or a gig or wanted to see his new girlfriend. I will 100% admit that I was argumentative and pushed and fought for him to see his son and quite often get angry if he didnt. But the thing is though, he had no idea how heart breaking it was to constantly have to explain to my baby why his dad didnt want to see him. To pick up the shattered pieces of a child's heart because daddy wasnt coming again.

I took the car when we separated. He didnt have a license and no intention of getting one ever. Because I didnt have a job at the time, we had to put the finance under his name but rego, insurance and everything else was under my name. Always has been. So when we seperated I took it. From day dot he has always blackmailed me and threatened to call the police and have the car reported stolen if i didnt ring child support and stop the payments. I couldn't risk losing the car so I did. He never paid a dime of CS. He called it "using marital assets as CS". The car was only worth 5k plus it was second hand. But I didnt want to lose the only means of transportation I had. So I stopped claiming what pittance of CS he had.

The amount of times he would harass and call me and text just to start a fight is insurmountable. Out of the blue i would receive texts or calls with some example of what a bad mother i was. How i had slighted him in the past or whatever reason he conjured up. He would constantly use my depression as a weapon against me and make out like i was mentally unstable and a danger to myself and my son.

When his new girlfriend got pregnant everything changed. It's like... he snapped... something in his brain snapped... he started keeping up with visitations and being more involved and at first I thought it was great! I thought the new baby had kicked his behind into gear and he was getting his shit together. But then he started getting... overinvolved? Started pressing me on who I was seeing, who I'm dating, whom I'm hanging out with. Where I go. All under the guise of needing to know because of our son. He even drew up a contract that said any male I intend on dating has to meet with him first before he meets our son. Like an audition. To past the test. I laughed and ripped up the conrtact.

At this point my son was still living with me. But my exs behaviour started to become weird. One incident was he had cancelled on visitation for the 3rd time in a row and our son was so upset. He said he wanted to talk to our son but my little boy didnt want to. I wasnt about to push the issue and make him so I said not right now, hes mad, try again later. My ex went OFF. It's like he wouldnt take no for an answer. He wouldnt stop messaging and calling, demanding I make my son speak to him. When I said no he kept calling and calling. I ignored the calls and messages and stepped away from the phone. I could still read what he was saying and then no where out of the blue he started saying I was suicidal and was going to kill our son and myself. He was worried for our sons safety. He was going to call the police. I thought he had truly lost it at that point in time and just left him to his own devices.

45 minutes later he shows up on my front lawn yelling out that he was performing a "safety and welfare check". I couldn't believe it! This asshole couldn't have his son for the weekend but could drive all the way over to my house to do that?! I was livid.

My ex wanted majority custody starting nearly 2 years ago. We had agreed when he turns 8, he could have him. That wasnt good enough for my ex. I got so badly harrassed and abused by my ex that I finally threw up my hands and said have him. If itll make you stop. Then have him. But a bit before that I had tried to start dating again. My son knew about it (hadn't met the guy but saw my messages and figured out I had a bf). My son told my ex that I had a new boyfriend and my ex did NOT like that. On the weekend I was kid free the new BF and i decided to go away for the weekend. Ex sabotaged it real bad. He rang me 1 day into having him and said i needed to come back and get him because he had stuff to do and didnt want to take son along with him. I replied it was his responsibility to find a babysitter and that i was away for the weekend and couldn't.

So BF and I are on a beautiful date. And out of no where I get a call from a detective from the police station saying my ex had called them and said I had been missing for days!!! I explained that my ex was just doing this to get back at me and sorry hes wasted his time. The police officer said he didnt believe my ex and he said it sounded like he was doing this vindictively but had to call to cover his ass anyway. I ended up in tears and had to reveal to my new BF what was really happening. He broke up with me as one of the reasons was he didnt want to deal with "baby daddy drama". I didnt blame him tbh.

So my ex managed to tank my new relationship and had harrassed and abused me so much I gave up majority custody of my son. I was broken. Beaten down and so ashamed that he still had so much control over my life. I just wanted the abuse to stop. I wanted him to just stop tormenting me and using our son to do it. I just want to be left alone in peace.

Hes withheld visitation many a times. Stopped me from calling and seeing my son. Degraded and abused me in front of our son. Blocked me out of my son's life. I dont know what goes on in my son's life anymore. My ex refers to me as "the belly mum" in his household. I'm not even his mum anymore.

I have to go back to mediation because hes broken every agreement in the contract. The latest one being hes stopping me from having my son on easter. We where suppose to go up north to see my mum and dad but out of nowhere my ex said no. I had to call mum and dad to tell them we werent coming and my dad was upset. He said he already got his grandson easter eggs and everything. He was devastated.

I know I have to go to court. I know I have to fight. But I am so scared. My ex isnt your typical DV ex husband. Hes smart and very manipulative. He uses the system to harass me and he hides behind our son as a reason to keep harassing me. I'm so frightened that when I ask for a restraining order the judge is going to look at me and laugh :(

I've been contemplating signing over my parental rights and skipping town just so the abuse will stop. But I cant do that to my baby. If I do... then I become the very thing my ex makes me out to be...

Please, I'm begging you mums. How do I do it? Please I need help