Surname Problem

Hello po. Good day. I have a problem regarding my surname. Since I was a child, Arbiz na po ang ginagamit kong surname. Which is the surname of my dad. Tapos po, nung kumuha ako ng Birth Certificate sa NSO, then there I discovered na Nartates ang nakaregister saken which is the surname of my dad. I'm going to college na po kase. Ang requirement po is Birth Certificate na issued by NSO. Ang files ko po since bata ay Arbiz. Pano po kaya yon? Do I have to change my surname or pwede na po kaya yung affidavit na yung Arbiz and Nartates are only one person? Thank you po. I really need an answer.

Nartates is the surname of my mom I mean.