Is delaying the final clearance after resignation for a period of one year and seven months, while others obtained it in a shorter time, and exploiting the legal waiting period of two years, considered an injustice that permits supplicating against the one who caused it?

Your being wronged is determined by referring to labor laws and agreed-upon conditions. It is not an injustice to be deprived of something that was given to others, which neither of you had a right to. If it is proven that you have been wronged, you are permitted to supplicate against the one who wronged you; for there is no barrier between the supplication of the wronged and Allah. However, the best course of action is forgiveness, through which Allah will increase you in honor and dignity, and it is a path to attaining Allah’s pardon and forgiveness.