I understand your frustration in this unfair situation, unfortunately there’s nothing to do in regards the visa 187 conditions and exceptions for you. If you are going ahead to dispute this unfair dismissal, you have to concentrate only on the work related issue but do not try to apply or spend money or time to get anything from immigration, unfortunately in this ocassion there is nothing either positive or negative they can do. Concentrate to get another job and start from scratch. Good luck