There is physical violence, but also non-physical violence. Anything we do that diverts our concerns at the problem, and not the well-being of our adversary may be violence.
Phone calls can be violent, if your intent is to annoy your adversary into change. That is violence. We need to make change through nonviolence means. Letters are good, phone call are good if done in the right time and the right manner.
First we need to gather more information, educate, and then "self purify" to make sure our direct actions are nonviolent.