There are some points why I did this.

I am engaged in the exchange, and mixed btc there before, there were no problems(I have many old letters of guarantee.). Up to the current moment.
True, I never sent such large amounts without any substantial guarantees.

This is partly my fault that I did not study the last messages, for example, there appeared messages that a person sent more than $ 30k(https://bitcointalk.org/index.php?topic=5168505.msg53771970#msg53771970) and he had problems.
The fact that the service began to experience various problems in January-February, and on February 19, it was moved to a new server.
I learned all this from public sources only when the order was gone.