This is an excellent video on SIM swapping from Europol:
Together with prevention advice:
https://www.europol.europa.eu/activities-services/public-awareness-and-prevention-guides/sim-swapping-–-mobile-phone-scam
A crime on the rise - 8 arrests made 9 Feb 2021 for sim-swapping that targeted celebrities in the USA. The suspects are believed to have stolen over $100m in cryptocurrencies by gaining access to and taking control of apps and changing passwords.