This is legally not a true statement.  You don't own the acronym PICISI.

The Official PICISI website is located at http://picisi.net    I am the only account authorized to speak on behalf of PICISI.

Unless you can provide an international trademark, I am in my rights to promote my own website, which cannot be confused with your site.

Perhaps we can compromise.  You call yourself PICISI.COM and I'll call myself PICISI.NET?  Neither of us use the term PICISI.