Student — 10th-12th marksheet

Dear Sir,
I have passed my 10th (2003), 12th(2006) from Grasim Vidya Mandir School, Nagda (M.P.) .
My full name is Nagendra Singh Solanki but in 10-12th marksheet my name is "Nagendra Solanki".
i.e "Singh" is missing from there.
In 12th admitt card i wrote my full name but because of 10th cirtificate that was not accpted.
But now i want to add Singh in my name.
So please suggest me -for the solution of this prablem what i have to do ?