What should a wife do who supplicated against her husband's brother's wife because of her injustice and accusation, and will Allah grant her victory despite the delayed response?

The wronged is permitted to supplicate against the one who wronged him, and Allah Almighty answers the supplication of the wronged, even if after a time. Forgiving the oppressor is better than seeking revenge from him, and repelling evil with what is better is superior to reciprocating a bad deed with another bad deed.