Good afternoon Rostyslav, unfortunately this has happened to most users of Freelancer including people who have been awarded projects.
Ensure that you do not start any work or event accept a project until the following criteria have been met:
1. Project awarded
2. Initial milestone/deposit created
3. Client agrees to release the first payment immediately after you accepting the project.
If they are unable to do this, tell then politely that you are unwilling to start on the project and keep looking for honest, legitimate clients.
Be careful at all time on this website, even if you do vey thing by the book and the client still doesn't pay, the Freelancer support team will not help you. It is left to you to contact the client and chase the payment even of they delete their account.