Verizon Communications’ war of words with Netflix escalated Thursday, as what began with a tweet is now pulling in the lawyers. The telecom giant sent a cease-and-desist letter to Netflix, demanding that the popular streaming service stop sending messages to customers saying Verizon’s crowded network is to blame for slow download speeds. “There is no basis to assert that issues with respect to playback of any particular video session are attributable solely to the Verizon network,” wrote Verizon general counsel Randal Milch to Netflix’s chief lawyer, David Hyman. “Verizon demands that Netflix immediately cease and desist from providing any such further ‘notices’ to users of the Verizon network.”