After millions have been stolen you really do not have any choice but to file some legal documents to get your funds back. Honestly you might never see your funds at this point.
Poloniex has stolen your money and you must take legal action!
If you are in the USA you have a few option at the federal level which will not get your funds back but will shut down the Fake Exchange Poloniex. It often takes more than one individual filing a complaint to start any investigations. There is no doubt in my mind that US laws are being violated at this point. Though I am not an attorney and cannot give you legal advice. You should seek the advice of a competent professional.
There are rules and legal rights you have when using an exchange if you are in the United States. The Security And Exchange Commission Can Shut down an exchange that is not conducting business according to the rules. You can file a complaint here: https://denebleo.sec.gov/TCRExternal/disclaimer.xhtml
Since this is a large theft of money. You might need to report Poloniex to the FBI here... https://www.fbi.gov/tips
Each state usually has an Attorney General that will sometimes listen to your concern and take legal action on your behalf.
Generally there has to be a certain $ amount stolen before they will get involved. Additionally if there are multiple people in a state or region the States Attorney may also become interested in such a grand scheme to defraud it's citizens.
Just because this is involving a crypto currency theft is theft and your property has been stolen. If we do nothing about this then many others will be stolen from in the future. If there are enough people we could possible start a class action lawsuit against Steemit and Poloniex and I think this would be a solid option at this point.