The recent Status ICO the caused many of our user withdrawl transactions to not make it onto the block chain - the transactions are just sitting there at 0 confirmations. When we ran into this happening earlier this month due to a different ICO, this impacted transactions for our ERC20 based tokens - we assumed after 16 hours of no confirmations that these transactions were dead/timed out, so reset them only to find that a few hours later the original transactions did make it onto the chain, hours after the resends did.
Being out of pocket a small handful of dollars isn't nearly as troubling as not being able to explain why this happens, why some transactions do and don't recover or what we should really even do in this situation. The general feeling here is that we have to protect both our user's funds and ourselves. As such we will be introducing a policy for reacting to ETH's "coin-of-the-future" behaviour, being to wait 24-36 hours and then resend the transaction. If that isn't enough for the chain to sort it's self out and continues to cause double withdrawls, we will be forced to consider delisting this nightmare again.
If you're running into issues with ETH, please be understanding we won't be able to meet our usual same-day support ticket resolution regarding withdrawls and transactions not on the block explorer yet - perhaps there is method to the madness of taking over a week to reply to a support ticket afterall.