"Hello, the following problem has happened...
The scammers forced them to log in to another account, and then changed their password and demanded a reward. My phone, there is a check, how can I log back in to my ID?"
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Classis ransomware demand: https://en.wikipedia.org/wiki/Ransomware
If you experienced a ransomware attack, the only solutions are pay the ransom, trash the device or perhaps a drive wipe and install of macOS will work.
Ransonware has succeeded in extracting payment in the hundreds of thousands of US dollars.
Doing a wipe and install will only get you back to production if you have uninfected backups and have a way to create a bootable flash drive: Create a bootable installer for macOS - Apple Support
https://www.cynet.com/ransomware/ransomware-removal-protection-and-prevention/