Failed in a Tough 500 Level Course: Seeking Advice on Grade Reconsideration

I am a graduate student, and I took a 500-level course this semester, which was very difficult. After receiving my final grade, I saw that I failed the course by just 3 marks, with an overall score of 62. I sent an email to the professor asking for a reconsideration of my grades, particularly because I received a lower grade on my final project despite positive comments. Since it was the last day of college, I wasn’t able to meet with the professor in person, so I followed up with another email requesting a discussion about my grade. The professor replied, stating that I needed to email him within 10 days of the grade being posted, which I did. However, now he is saying that it is not in his hands and is not taking any further action.

I studied hard for this course and feel that the grade does not reflect my efforts. What should I do next? Any suggestions would be greatly appreciated.