To file complaints the Italian authority for telecommunications (AGCOM) requires using a dynamic PDF, which can only be read with Adobe Acrobat. It says "for other compatible applications, consult the websites of their manufacturers" (but which other have this feature? it's not said).
http://www.agcom.it/default.aspx?message=contenuto&dcid=200
Note that THERE IS NO ALTERNATIVE way to present complaints.
Cheers
Carlo