in fact they do not send any calls to the telephone number or any text messages to validate the withdrawal
They have never responded to the emails I send every day and in the chat they always write that the operators are busy
Wait, I am not sure I understand this part correctly. You're actively in chat with them? And whenever you told them that you can't verify [or other reason] they write that the operators are busy? If you happen to be in contact with them through live support and they still replied to you, kindly just redirect them to this thread by telling them that you'll appreciate if the staff who manages their bitcointalk account rep will get back online and address the matter here.
Kindly provide us with screenshot of that conversation I proposed above after you managed to do it.