From my brother italian passport- i can get my own ?

[or100cohen]

My name is Allegra Mafalda Scetbon, daughter of victor and marie Scetbon

me and my father had italian passports.
my brother Guido (R.I.P) have a passport too but i don't know if it's because he is married to italian citizen


Victor was born on 05/21/1902 in Monastir in Tunisia.
Marie was born as marie Salfati in 1902 in the city of Beja in Tunisia, and died around 1939 in tunis,tunisia.
I was born in Tunis, Tunisia on 29/11/1929
Guido was born on 02/12/1925 in Tunis Tunisia
I have my birth certificate that I received from service central de l'état civil à
nantes.

i have talked the italian embassy , they said i need to get my italian birth certificate .
does it possible that i have two birth certificates ? , if i do
how should i get my italian one ?
they said i need to check with state of livorno , maybe my record is there , but they did not replayed me by mail .

somebody know if i can use my brother italian passport to get my italian birth certificate?
Best regards,
Allegra Mafalda Scetbon

my birth certificate from central de l'état civil à
nantes: http://imgur.com/a/sgk0a

My brother passport :
http://imgur.com/a/6Kum0
3 pictures in the link , scroll down to see .