That happened about 10 hours ago. After many message exchanges with the support staff I got for quite a while no reply from them other than "they're looking into that" and that "it has been sent to a cex.io supervisor"
I finally (after insisting a lot) got the following message from the support staff:
"it appears that the AutoPayout feature glitched, making transaction stamps in user's accounts but not always actually provisioning the transaction to the block chain. I think you are one of those that has the stamp with no consequent withdrawal, I have raised the urgency of your ticket and linked it with the group of incidents that share this feature. It may take a little time as there a few of these tickets pending at the moment"
... is that only happening to me? or are there more cases? I am very worried.
Since the support staff has explicitly acknowledged that it is problem on their end (AutoPayout feature glitched), you shouldn't be worried too much. Give them a day or two to solve the problem.