UPD2: Verification completed. The withdrawal of funds is unlocked. I will continue to work on this exchange. We agreed that I would only make transactions between trusted persons. These are banks and large exchanges.

As a result, what can I say. The check took two weeks. It may have been speeded up by the publicity on Bitcointalk and Reddit.
I remain on this exchange, because there was no strong delay in the process. People report 9 months. Perhaps they could not confirm the origin of the large amounts deposited on the exchange.
What exactly was the problem with my account, the exchange does not report.
What did they check. Proof of the origin of main founds deposited on the exchange.
They were also interested in transactions for depositing and withdrawing bitcoins. Including very old transactions from 2017, 2018. On them, I was able to give information only in words.
It turns out that there are no problems, inputs and outputs should be between trusted parties, i.e. banks and major exchanges. Transactions of buying and selling cryptocurrency, which are started or withdrawn from the exchange, must be logged by yourself, if the history is not stored by the second party. And be ready to prove the origin of the funds being transferred.