Xiaomi has reportedly stated that users affected by the recent bout of remote phone locking can now start using their devices again. Apparently, the locking of Xiaomi, Redmi, and POCO phones out of the blue in prohibited countries such as Cuba and Iran was carried out as part of an investigation into grey market practices.
https://www.notebookcheck.net/Xiaomi-eases-up-with-remote-phone-locking-in-prohibited-countries-such-as-Cuba-Syria-and-Iran.561196.0.html