I'm having the same Problem.
I opened a ticket... they said they look into it.
...
this is really troubeling since I bought many Ether... and now they are stuck.

EDIT: I don't recommend buying ETHER at Poloniex. Many Transactions went perfectly fine, but two of them didn't went through although Completet. Be careful...
My Ticket is open for more than 1 day... let's see how long it takes for them to give me my ETHER