Even if one insists that the serpent (NOT Satan) lied about them not ever dying, God lied first when he said their punishement would be death the day they ate of it.
God was very compassionate. He did not lie still - Adam and Eve eventually died. God still gave them a chance to live. God however wanted the earth to be full of people, He could have just wiped out man kind but He didn't.
Satan lied. Adam and Eve still died. If they had obeyed they would have been alive up to this day on earth.
BlessedStar