Central Board Of Secondary Education [CBSE] — I am complaining about getting very less marks in Maths in 10th class

Address: Jawahar navodaya vidyalaya thawe Gopalganj (Bihar)

Hello Sir/Mam,
I need your immediate assistance here as i am very disappointed and frustrated about my Maths mark for class X this July 2021. As i have done exceptionally well in my pre-board exams and and in fact in previous class IX & scored 90 plus mark in each subject. Even though my subject teachers are also shocked to see this low marks. Also when i visited my school for the same concern they told me that we have sent great marks considering pre board marks and class IX.
But we don't know what went wrong with CBSE Board. Please do the needful support and resolve my concern asap.
My complete details are as follows :-
Name - Priya Kumari
Class -Xth
School :- Jawahar Navodaya Vidyalaya
Father's name:- Ajay Kumar Pandey
Mother's name :- Nilu devi
School Code :- 69042
Roll No :[protected]
Reg no :- P/1/21/69042/0033
I would urge you to look into this matter very seriously and resolve my concern if anything wrong went from your end while updating the marks.