You Have two main options which depend on whether you are employed legally or not, I will present them as plans A and B respectively. Each step of the plan is an oppurtunity for your employer to pay you if they do then obviously the plan may be discontinued as it has been succesful.
A)
1. Dig up any evidence that you did actually work, ask in person to be paid.
2. If this fails however there is an active union presence in the workplace contact the union rep. If not contact the relevant union directly and ask for assistance, you will likley be suprised at how willing they are to help.
3. Contact a lawyer, obtain signed affidivats from your collegues indicating that you did work.
4. Write a letter yourself to your employer asking politely to be paid (attatch affidivats but do not mention that you have a lawyer).
5. Instruct your lawyer to write to your employer asking for your pay and threaten legal action if you are not paid.
6. Sue them for your lost wages, interest that you would have gained on them, your legal fees, a sum to compensate you for your time spent trying to be paid (eg your hourly rate at work multiplied by however many hours you worked on getting paid), any other expenses you can think of.
B - If you were employed cash-in-hand
1. Dig up any evidence that you did actually work, ask in person to be paid.
2. Threaten to contact local media eg local paper and community radio.
2. Contact the ATO and dob in your employer, to make sure you still get paid make the point that you were employed as a contractor and as you presumably have earned less than $6K in the last year do not need to apply for an ABN.
3. Join a Bikie gang and extort the wages from your employer then firebomb your employer anyway.