Awesome question! Many people are astonished to hear about North Korean refugees still contacting their families and friends back home, especially with the tight control.
Once North Koreans resettle in South Korea or other countries, they typically want to re-establish contact with their family members or even friends in North Korea. In recent years this has become increasingly possible through broker networks that can smuggle money and/or Chinese mobile phones to families remaining in North Korea. Chinese mobile phones can be used from many border regions to connect to the Chinese network and make direct phone calls to South Korea or even to the U.S. This line of contact and the broker networks that facilitate it can also be used to send cash, which is smuggled in from China and then dispensed to the families of refugees after money is transferred to the broker’s account and the necessary phone calls are made.