Daniele,
In that case you should be able to select it by clicking it with the Selection Tool (black arrow), unless it is locked or something else is hindering you; you should be able to see the artwork and whatever in the Windows>Layers palette with the relevant layer(s) expanded.
It may help if you show a screenshot of the artwork with the Layers palette also shown, and preferably also the Appearance palette.
I think I solved doing this: create a new AI file with an artboard size like 1920 x 1080. Inside of it, I paste the copied object from the original file and adapt in it. So now, I have the logo with the desire size and amount of white and space all around. It's ok like this or?
Just another small and quick question: I tested then this new file and if I export for web in a large size (3840x2116 like...) I have an excellent quality but If I saved it in like 1020 x 500 for example quality is awful and super "pixellated" ... isn't it a vector image that I can resize like I need without quality lost? Sorry but I'm new to this world but I need this logo so bad