The Buddha taught many different teachings to suit the disposition of different disciples and guide them along the path. This is particularly true regarding the teachings on selflessness, which is emptiness. Since people of his day had strong belief in an extended self, atman, he began teaching them there is a self. Slowly he introduced them to no self, or anatman. Having introduced no self, he guided his disciples to subtler notions of no self. All these teachings are incredibly skillful to guide disciples along the path to enlightenment. Thus they are all complementary and not contradictory.
