If your transactions are on a LISK blockchain explorer then you will get 120% bonus don't worry - double check. You can also send an email to
tec@ark.io and our dev will take a look at it.
To join our slack go to :
https://ark.io/join-ark-slack to get auto-invite.
and what if poloniex is holding my lsk withdrawal for several hours now?

Like cannan said, cancel the withdrawal, sell your lisk to btc,withdraw btc to bittrex and withdraw lisk from bittrex, that is much faster than waiting for inefficient polo. At least you can handle it by yourself, not rely on polo