Further to recent postings about the telephone numbers that come up on your phone display with these scam calls, there is an article on the BBC website about what they call number spoofing that is used to make many of these calls. They say that it possibly will not be eradicated until about 2025 by when a different system will be used to display the correct numbers. See:
https://www.bbc.co.uk/news/business-56934517