After a Princess cruise we had the same scenario--both our suitcases out to the hall at the same time, my husband's never maade it to the terminal.  Or, more likely, it was picked up there by another passenger by mistake.   Princess helped us look, but otherwise had no other way to help.  They did give us a free ride to the airport!!.  Received a measly $250 from them as compensation.  Even the suitcase cost more than that!