Damn that’s bullying, discrimination and inappropriate workplace behavior all at once, I’m sorry you had to/are having to go through that 
is there a tribunal or a workplace advocacy group you can go to? Or join a union to get their legal team on it?
Failing that, sue them and see how their small company deals with allegations of a toxic workplace!
What @Gontranno47 said. And if you can, if it’s an option for you, go with the biggest and most well-known law office that you can, so that it gets as much exposure as possible.
And collect every item of workplace bullying you’ve experienced since and from now on, so you have a case file full of them. And once you’re done with the legal route, sell the story to an online journal. I normally don’t go for such an aggressive route, but otherwise they’re free to continue doing it whoever they hire
Plus, it will give any other smaller companies who are doing similar things and believe they’re below the radar serious concerns once they hear about it. It could potentially help others in a similar position. When this behavior is systemic like this, the only way to truly deal with it is full exposure. Otherwise, if it only deals with the individuals who personally participated in the behavior, it still opens up retaliation down the road when everyone moves on from talking about it, once other reasons are thought of to take disciplinary actions against the complainant.
There are also sites where you can rate your (former) employer where you can write that. That can be extra painful for companies that are small and therefore like have few or no other ratings yet.
Though I do not want to suggest such a platform as I think you need to be a bit careful it is a legit one, and my experience is limited to my country. Surely you should keep evidence at home in case the company tries to get such a review removed.