Carelessness of CBSE

Dear Editor,
This is regarding the carelessness of the CBSE.
My little sister appeared her tenth exam, conducted by cbse. She wrote all the subject very nicely and result also came as expected except mathematic marks in mathematics.
At that time, I was also confused so I rushed to her school ‘new master academy’ and i met the principal enquire about the result.
She was shocked to know that my sister who is good in studies scored zero in Maths. The principal suggested that I apply for reevaluation.
We go the reevaluation done and after around 15 days we have got the answer.
It has disheartened us because the paper we got from CBSE was not that paper which was written by my little sister. The code number was different and set no was also different.
So, I have gone to the exam centre where she wrote her exam to see the sitting plan just to confirm whether the question paper code that she was given was same or not.
In sitting plan, there was nothing wrong with question code and set no. Everything was same as my sister told me. How it could be possible that person who secured 93,95,75,68 respectively in other subjects got zero in mathematics?
As a parent, I am writing this letter to CBSE please stop playing with innocent students and this kind of carelessness will deprive thousands of student.
A citizen