i've been playing for multiple days now and whenever I type /grade it says I have a certain amount of time until I reach the next grade, but the timer keeps restarting and I can never get past grade 7. How do I grade up?

Hello there! I've been playing on school rp for awhile and a couple or so months ago, I noticed my grade had been glitched. I have played for over 48 hours. I should be Grade-12 but it says Grade-7. I have requested it to be fixed about 3 or 4 times now yet whenever I go on the server it still...