cex is a SCAM.
I deposited 800 over two weeks ago and my money is nowhere to be seen.
There is no customer support. Nobody answer my tickets.
Money stolen by cex.
They pretend to be an exchange but they are thieves.
Not just you either but a lot of other people have similar issues with cex.io.
I actually wouldn't really hesitate calling them a scam right now. I see their ads every single day on youtube, which shows that they are still willing to spend money on advertising their business. Yet they don't seem to have spent any effort in maintaining the accounts of their customers which really sucks because i remember they were one of the best places to exchange fiat to BTC before, with cloud mining as well.
Keep contacting support and hope to see a response. That's pretty much all you can do.
If you look at the scam accusations every exchange is a scam. I can't seem to find any exchange without scam accusations. I personally have used CEX.io and everything went fine. It's also true that most of the times is the user's fault. Did your bank process the deposit OP?