It has been long time and it is easily to argue it in the court as mutual agreement as no late fee. Otherwise they should not ask for it after you moved out and received final bill. (note: final bill is final, they should not pursue any more than the final bill.)
For small court claim, you can ask any friend to represent you. No attorney needed. Have a authorization letter ready (notorized). You also can do it when you are back to State.
