This is a normal situation for Poloniex this days. Just make a quick search and you will see the amount of threads in here and on Reddit about Poloniex delaying peoples withdraw and open support tickets for days without any answer.
I believe you will get your coins, but it may take some time and there is really nothing you can do about that.
Some examples:
https://www.youtube.com/watch?v=U3CFXc3WyVA