Write a statement to the Cyber Police at this link (https://ticket.cyberpolice.gov.ua/) or report your case by calling +0 800 505 170.
I also recommend contacting the cellular operator and informing him of the contacts of the fraudster who demanded money. After that, employees will not only block the subscriber, but also impose fines on him. If several complaints are received on the same phone number, then the cellular operator will file a criminal complaint against the fraudster.
You also have the right to immediately contact the police with a request to check the subscriber for fraud and demand that he be brought to administrative responsibility. The application must be submitted to the nearest police station. It must be made in two copies. On one, police officers will put a mark of acceptance and assign a number to it. Then the application will be submitted to the inquiry body, within five days a decision will be made on whether to open a criminal case or not.