Well...there are 3 "Telephone Scenes" in Silent Hill 3... In the first one, Heather was talking with Harry Mason.And in the second and third ones, she was talking with Leonard Wolf. Do you mean when Heather has "Happy birthday" sang to her? When she's on the phone and that happens, she's talking to Stanely who, I believe, is not revealed in the game. She is talking to a order member cause Stanley is dead and Leonard is not the one who is speaking to you there so a order member who helped leonard.