I did a similar thing with almost 5000 XEM. I forgot to type my unique code in the memo field. I opened a ticket 2 weeks ago. It took 1 week to get a reply. I was asked to confirm the transaction id and to make a small transaction from the original sending account into my account, but using the proper code this time. I did. It has now been a full week since that happened and nothing. Poloniex support is heinous. Ever go into their Trollbox? Half the people are begging admins to check the status of their support tickets. Good luck to you, please be sure to post a follow up to let us know the results. Check out my post about this experience here: https://steemit.com/poloniex/@infinite-monkey/what-s-your-poloniex-horror-story-share-it-here