As was mentioned by someone else here, the OP should find out if the money that he deposited to his trading account has a connection to Australia. If what he deposited was held in an Australian bank account, then he can submit a complaint to the AFCA. With the complaint, he should submit any emails that he had with the broker, trading account statements, bank records, and credit card records.
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It's not automatic entitlement that AFCA or other jurisdiction will accept the complaint.
Even if you pass that hurdle, there is no guarantee that you get a ruling in your favor. AFCA does consider if the client mitigated their losses. I've reviewed some previous AFCA cases where they did see the broker did some questionable things, but also saw the client doing equally questionable things or saw that it wouldn't have prevented the client loss anyway.
You really have to prove the broker did something that breached their obligation and was also directly responsible for the loss. Different financial products will have a different interpretation of what is expected. With CFDs, the product is already complex. Was the loss caused by the broker directly? Can you show or reproduce the exact misbehavior that caused the losses?
I don't know who "Giambrone" is but in Canada, people complained and were successful.
For Canada, I would need to look at the case file. Do you have a link to the specific cases against Vantage where Canadian authorities were able to compel non-Canadian broker (broker with no office or company in Canada) to return funds to clients (whether the clients were Canadian or not)?
Normally the country where offensive behavior is detected would just issue scam/unauthorized warnings.
There are laws to protect investors who "lost in trading" or those who have been manipulated.
The best I've seen is negative balance protection. But then again, those same jurisdictions also have limited leverage to 1:30 (and that is for major fx pairs only, lower for other cfds). If you want more leverage, you need to apply for professional/wholesale status, in which you would lose your retail protections (as you are assumed to be responsible enough to monitor/handle your positions yourself completely).
And some other laws that limit the "gamification" of deposit/withdraw operations or limiting ability for broker to induce trader to trade.
See
this press release
Ultimately, the trader has to take some responsibility also. Especially when going offshore.