Send them the invoice and give them the standard time to pay.
If they fail to pay then you can issue them with a Statutory demand.
It is the alternative to suing in court.
You rely on the agreement you have with them.
Here is some detailed information.
If they do not pay in 21 days they are deemed insolvent and you can put them into liquidation.
You will need to hire a Solicitor in Australia to do this for you.
He would be foolish not to pay.
Also you can have the agreement looked at by the solicitor and have them give you more detailed advise on compensation if it has been terminated incorrectly but the other side.
But you have to send the invoice and he has to fail to pay in time before you can issue the demand.
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