If your wife did not follow all the steps the DMV listed, she could be liable.
BUT even if she was remiss in some steps... like the worst being to have not removed the plates (I hope she did that.), this is not the end of the world.
HOWEVER, having had something very similar happen before to myself, I suspect very strongly that what another poster says is the truth, and that the tow place is following the laws to give you a chance to claim property so that they can seize it legally and sell it.
Just ignore the calls, as there is nothing you can do.
Just because a creditor is calling you does not mean you you credit or life is ruined or even damaged.
This is some tow guy in another non-adjacent state...
Raise you threshold for things on your back because this is NOT a big problem.
Tow guys make money by seizing and selling unclaimed junky cars. Not by suing people from 4 states away who have a strong defense.
This would be totally different if you were like "My car, my baby, they found you..." Then the tow guy would have the upper hand.