  With the use of the band structure calculations we demonstrate that
previously reported [Nat. Materials {\bf 3}, 48 (2004)] experimental crystal
and magnetic structures for NaMn$_7$O$_{12}$ are inconsistent with each other.
The optimization of the crystal lattice allows us to predict a new crystal
structure for the low temperature phase, which is qualitatively different from
the one presented before. The AFM-CE type of the magnetic order stabilizes the
structure with the elongated, not compressed Mn$^{3+}_B$O$_6$ octahedra,
striking NaMn$_7$O$_{12}$ out of the list of the anomalous Jahn-Teller systems.
The orbital correlations were shown to exist even in the cubic phase, while the
charge order appears only in the low temperature distorted phase.
