Who do I complain to if University failed me by accident?

Long story short, instructor did not submit my grade on time into the university system and so I failed a course. Have to retake and pay for the course again.

School dean and registrar both refuse to do anything and insist that it’s too late to change the grade anyway and told me to just retake.

Because of the failing grade, I was not able to enlist in the next course this sem and so my graduation will end up delayed.

What options do I have? Seems pretty unfair to me.