I too have lost coins with Poloniex. I withdrew some coins to my own wallet and I got a "COMPLETE:ERROR" code.
This code means that the coins were NOT moved. However Poloniex does NOT put the coins back into your account. Instead Poloniex freezes those coins and makes you go through their customer support "TICKET" system.
The system however can take weeks and I've heard even MONTHS before they even get back to you!
To make a long story short I used Poloniex and lost several THOUSAND dollars worth of coins.
Poloniex doesn't seem to care at all about customer service or that they are loosing their customers hard earned money and coins!!!!!
If I ever get my coins back I will post about it and hopefully I will get them back.
But in the meantime!
BEWARE or Simply DON'T USE POLONIEX.
Is there anyone who has the same problem like me. I did withdraw my coin and in history written completed but I did checking on the tx. no results for the tx? and I see my address no incoming transactions? I made a support ticket but no one answered. very disappointed with poloniex service.
There are similar stories to yours on this reddit thread.
https://www.reddit.com/r/ethtrader/comments/6uvrl4/poloniex_withdrawals_megathread_post_here_if_polo/This is one example.
https://www.reddit.com/r/ethtrader/comments/6uvrl4/poloniex_withdrawals_megathread_post_here_if_polo/dlwruxr/So this happened to me last week.... submitted a ticket immediately and no response.
Then 2 days later, I happened to glance at my wallet balance and my ETH was there. The txid listed on the withdrawal on Poloniex was changed to a valid one.
Very weird.
Maybe your withdrawal will eventually get processed, and they will change the transaction ID to a real one.