Contact Paypal and file a dispute. I got a refund for the monthly amount that they should not have charged me for.

Freelancer is devious, dishonest, make a complaint with paypal, then mail a certified letter notice of pending lawsuit to freelancer headquarters, as i am about to do. Contact the Better Business Bureau and the white collar crime department of the police authority in their jurisdiction in Australia. Freelancer gives a bad name to the entire internet world.

I would file a dispute with PayPal, then find another site like Upwork, Guru or PeoplePerHour.

Where did the money come from to fund paypal? Reverse it at source

If it was from your bank. Ask your bank to file an investgation and they can reverse the transaction. If it was with paypal file disbute with paypal.

Stop-loss. Try to reverse payment through Paypal. Then suck it up, close your account on freelancer.com and forget about this "by scammers for scammers" fraudulent paradise.
You are not the first and not the last ripped off by Freelancer.com

First, make a support ticket with all your questions in a TO THE POINT fashion. Then try for the LIVE CHAT with the same purpose. Wait for their response. Review their answer, most likely they won't respond you in a TO THE POINT fashion. Then if you are not satisfied, try PayPal dispute.

I have repeatedly asked them WHERE/WHO TO CONTACT IF FREELANCER.COM FAILS TO SATISFY ME WITH ANSWERS but they never answered that question. Under this scenario, Department of Justice, Australia seems to be the last resort.

As other people advised here, you can go with any of the legal opportunity to file dispute. If we go through normal service tickets calls and all, they keep saying that is how it is and if you confront them with valid point then they will stop answering you.

No idea. Talk to them.