How did Malala transmit information to the BBC reporter?

After the Taliban take control of Malala's hometown of Mingora, the young girl shows immense courage in speaking out about what life is like under this fundamentalist terror organization. But she has to do so anonymously, otherwise the Taliban will track her down and kill her. Her point of contact with the outside world is the British Broadcasting Corporation (BBC), and they allow Malala to write a blog about life under the Taliban for its Urdu Service.
But this is a very tricky task for Malala, to say the least. With the Taliban in charge, there are frequent power cuts. Not only that, but the Swat Valley where Malala lives has very poor internet connection. So the only way that Malala can transmit information to the BBC is by using her mother's phone. In this way she's able to let the outside world know just how repressive life under the Taliban really is, especially for women and girls.