My iPhone was blocked by scammers

Good afternoon, there was such a problem, someone else's icloud was fraudulently tied to my phone and my phone was blocked, yesterday around 11 00-14 00 ,an icloud of a moshenik who was tied, a person demands a ransom for untying,tell me what to do,there is a box from the phone and there is a check what to do in such a situation

[Re-Titled by Moderator]