When discussing Antigone and its themes concerning law, morality, and (in this case) authoritarianism, what you need to remember is that the Ancient Greeks tended to be moral realists. This is certainly the case in Antigone, where Creon, in his decision to proscribe the burial of Polyneices, defies those traditional obligations that the living were understood as owing to the dead (along with the gods that uphold them).
Of course, this does not prevent Creon from breaking moral law, and this is ultimately where the lack of accountability enters into the picture. Ultimately, Creon is a tyrant who dominates political life within the polis, such that (in his mind, at least) he need not hold himself accountable to anyone or anything. No one can countermand his orders: not the citizenry, not his family members, and not even the seer Teiresias.
However, all this being said, there is a second half to this equation: while Creon might not hold himself accountable to anyone or anything, this does not change the fact that the moral law still exists. The citizenry of Thebes sympathizes with Antigone and recognizes the degree to which Creon has transgressed, as does Creon's son, Haemon, not to mention Teiresias himself.
Meanwhile, on a cosmic level, the universe of Antigone is one where the gods exist, and they do have the power to hold Creon accountable, providing divine retribution for his transgressions. Thus, the play ends in tragedy, with Creon's family destroyed.