How did they managed to purchase 400,000 SIM cards? In my country, it is very tough to get a SIM card. You need to show your ID cards. And if there are more than 4-5 cards issued against your name, then usually the cops will appear at your doorstep. How these guys managed to get 400,000?
Depends on the country some vendors just sell them on the street and you can buy as many as you want, but I guess it really depends on the country social media generating likes I guess is a good way to build reputation unless you get caught doing it of course ^^.
The question is how do you use that many sim cards between three people ... it would take a while in my opinion nice investment into the future though.