one rule for the use of "the": it is not used before a general term...representatives is a general group. Don't you agree?
I agree with Zobdek. It is unclear whether "the" is necessary in this context.
They are the representatives is a perfectly valid sentence that has a slightly different meaning than they are representatives. In the first one representatives is a specific group or type of representatives the second one they are the general type of representatives you are talking about. Without context both translations of the sentence should be correct.
In reference to "spokesperson" does it matter when you would use in a conversation representantes or portavozes which I think was also used in this series of lessons?