How did Poseidon punish the Phaeacians for helping Odysseus?

Poseidon punished the Phaeacians for helping Odysseus by turning their ship to stone as it returned from delivering him to Ithaca. He then caused a massive mountain to rise up and block their harbor, effectively isolating them and preventing further assistance to travelers. This act served as a warning to the Phaeacians not to aid mortals against the will of the gods, particularly in defiance of Poseidon's authority.