The Helen in that play is hated, as she is in Euripides' Iphigenia in Tauris (c. 412 BCE) and Iphigenia at Aulis (c. 405 BCE), and she has no phantom double--though Iphigenia, who (especially in the former play) functions much like Helen, has one: she is saved (from being sacrificed by her father, Agamemnon) by a deer ex machina sent by Artemis to take her place.
From Splitting the Difference: Gender and Myth in Ancient Greece and India
by Wendy Doniger
