What is the ruling of Islamic law concerning a marriage contracted under duress, with the forging of the girl's signature, and what are the implications of this after consummation, and what is the way to lift this injustice from her in light of the father's obstinacy and the judiciary's dereliction of duty?

It is not permissible to compel a mature, sane woman to marry someone she does not desire. Disputes of this nature are referred to the Sharia court.

If the girl is unable to prove her father's coercion and the forging of her signature to the court, she has the right to seek a khul' (divorce initiated by the wife).

Just judiciary never sides with the oppressor. It is not permissible to think ill of a Sharia judge, and obedience to his ruling is obligatory.