I also recently have a 11+ BTC withdrawal with a fake transaction ID. My other smaller withdrawals went through fine. i'm guessing a larger withdrawal is causing delay.
EDIT: I have received the coins finally, about 12 hours later
The Bitcoin blockchain is clogged up right now. Over 200,000 unconfirmed transactions according to Blockchain info ATM.
https://blockchain.info/unconfirmed-transactions. You are lucky your transaction only took 12 hours. I am waiting for a withdraw from another exchange that I did 24 hours ago and am still waiting. Can't speed it up with ViaBTC transaction accelerator because they are full. If you want to make any moves in the near future, you may want to try converting your funds to Litecoin and move them instead.
This is only the closest possible solution of this when you do really hate on waiting game. We cant blame them since the blockchain do really have the problem because of the pile up of unconfirmed transactions throughout the network.Seeing on this thread its quiet old but still the issue keeps coming back related on poloniex withdrawals.