Just look at their trustpilot reviews.

https://uk.trustpilot.com/review/cex.io

Cex used to be top of the game, but has now gained many terrible reviews.

CEX.IO is ranked 51 out of 52 in the category Currency Exchange

CEX.IO is ranked 39 out of 43 in the category Electronic Payment

Gone are the days of being number 1 in both those categories.