CBSE — regarding change of optional subject

Address:

Gautam Buddh Nagar, Uttar Pradesh

I am a student of class 12 in commerce stream.my school offers maths and entrepreneurship as an optional subject .I had maths in class11 but since I scored very poor marks in maths I decided to change my optional subject from maths to entrepreneurship. I consulted school authority and asked if it was possible to change subject in class 12 .they said it is and thus I gave them application and by beginning of the new session of class 12 I was told by school authority that my application is approved by CBSE and relative authority .So by the month of April [beginning of new session] I am regularly attending my entrepreneurship class. Now when our course is in middle suddenly out of the blues I was informed by my school that CBSE board has declined our application and now I have to study maths. Now when maths syllabus is already completed partly how I am supposed to study maths knowing that I am not good in it.so now my whole future is on stake .I am unable to understand whose fault is it either CBSE or my schools and what I am supposed to do .please reply at the earliest possible.