The author works in the UK and there's one company listed on his LinkedIn that provides the services he described, which is situated in Cambridge. The description of the product seems to indicate that the software is written to allow carriers to lock out people who stopped paying, mostly targeting people who'd normally have trouble getting credit for their phones.

Unless the company specialized in sales outside the UK and likely also outside the EU, I think this company is probably breaking the law, as are the carriers using their services. I doubt the people who buy phones on extended credit will have the cash laying around to bring up a lawsuit, though.

The phone numbers generated for testing were in South America, but the app can block anywhere in the world from any country in the world, including UK. That stuff blocked random phones on the globe, if that is not clear enough.

UK common law is pretty prevalent all over the world