I am in the same situation. I have asked to withdraw USD and GBP, in 3 separate occasions, in December. For all of them I have received the e-mail confirming the withdrawal, yet I received nothing so far.
The first transaction, amounting to around 20.000 USD, was confirmed in date 2017/12/26. 20 work days and counting.
All the support tickets I opened about the issue got marked as "SOLVED" after an hour or so (probably automatically) without even a word of explanation, no response at all! This is at best a very unprofessional behavior, and indeed feels very scammy. If the transactions have been done, it should not be a problem to provide their details (as I asked in the support tickets).
I do not believe (yet) that CEX is a scam, but the customer service and the withdrawal times definitely need to improve.
I will post an update as soon as something changes.
Username: up114383891
Transaction IDs: 5251477810, 5266045999, 5315844210
I'm in the very same situation!
USD withdrawal for around 19.000 USD confirmed on 2017/12/26, still no money received. Please update us if you solve this!
My data
UserID: up112944475
Transaction ID: 5251048325