These two transactions are clearly visible on steem blockchain but even after poloniex enabled back steem and sbd they're still not in my wallet there:
https://steemd.com/tx/8c71fdae38c5244be4060e9f33197d4554340344
https://steemd.com/tx/94bbfc9d220db48e9051f3985d74bce26bb0ddaa
As a person who lost 6 BTC when MTGOX went under the ice, I have to conclude that this pattern of delays and zero response rate from poloniex support mimics exactly the behaviour during last days of an exchange. I hope I'm wrong, but I just want to point it out.
In the meantime, I have switched to Bittrex completely.