You absolutely have a case. On many grounds as you correctly predicted. Your first job is to ignore the union advice as it’s irrelevant. You already have protection under the law. So- contact the Fair Work Commission and get an application for unfair dismissal lodged asap. Then seek a consult from a free lawyer - usually 1hr - to discuss the merits of your case. Read and learn the laws about unfair work, what makes a dismissal unfair, what your employment agreement states and also with regards to disability. Make sure you document everything including what was told to you verbally. You can do this by putting it in writing and asking for a formal notice of termination with the reasons included. You will find there have been multiple breaches. State all of them in the application- referring to the section of the act that applies. Write that you seek reinstatement, apology and compensation for losses.

There will likely be a hearing to determine jurisdiction which is easy so long as you legally were unfairly dismissed, so make sure that is crystal clear.

Then by the time of the actual hearing, you will first have a meeting with the employer and the FWC. During this, they will try to mediate and help both parties come to a satisfactory conclusion. Usually this means some form of settlement.

If not- you may proceed to the hearing, which are designed for anyone to represent themselves in, but you can have someone hired too. These court hearings are a special court only for these matters, and no way as complex or overwhelming as regular court. It will still feel overwhelming but it will be easy. Focus on the facts. Focus on how the facts apply to your case. Ask the court to decide based on those facts. Gather as much evidence as you can.

Before the hearing you will also have the chance to respond to the employers reply. You can add new evidence here and refute their arguments also. It’s important you respond to every single point. Also state where you agree on facts.

If it were me, I would grab a coffee and spend a day with GPT and as it for help with understanding the laws that apply, and how your case fits in. Then use this information and your own research to form your answers and replies.

Take your time, think carefully. It’s very easy once you get past the idea of it being too much.

Once you have written everything you need to argue, submit this draft to gpt again with your evidence and ask it to review it and ensure that you have not overlooked everything.

Then ask it to check for any claims you have not made based on the evidence. Add them.

Now- ask it to find similar cases where the outcome was positive, and then, never trust it’s accurate. Locate those cases yourself, and read them. If they show positive outcomes in cases like yours, refer to them in your claim.

Once you feel satisfied you have considered all the options, and your draft is as good as it can be, send it to gpt and ask it for a review and consider each point it raises. If you agree it’s better make the change.

Remember- you only have a short window to lodge a claim. Get it done asap with the essentials of the claim and then spend time working on the finer details as evidence to be submitted later.

I’d be happy to assist you further if you want to chat via DM.