Help me with problem during Hard drive format?

I format my external hard drive few month ago to use it with xbox
but some kind of error occurred during the process and my external hard drive is recognizing only part of its actual capacity
I was dividing the 120GB into two (30 and 90) and after formating only 30GB part is recognized
I was wondering if there are way to recover it back to way it was
(by the way I don’t know which program I used to format the hard drive )

Thank you and Happy New Year ^^