I wasn't sure where to post this..

I'm just wondering if anyone knows anything about the legalities of surnames.

My son was given a hyphenated name, i had applied through medicare and also centrelink to claim for baby bonus but i only put his surname down as my last name when completing the forms as his birth certificate was not yet lodged.

The trouble i'm having now is that i have only ever used my last name for everything medicare is in my last name, centrelink, doctors, etc.. but on his birth certificate he is legally a hypenated name.

Can i get in trouble for this?

Any info would be great