Since you got a reply and assured you that they are working on your document, let them do as they are. In fact, document verification should not have taken so much time if they were really serious about this problem.
today they asked me to provide a document about my bulgarian company.
ok, went to the bulgarian tax agency for the fresh reference and sent it to cex.io
Let's see if they verify this document and allow you to withdraw your funds. Exchange holds your funds so you have to work with them to get your funds back. Here the exchange rules are trying to solve your problem, and since they are still connected with you it means that your problem will be solved very soon. So be patient and wait for what they say about the next update.