My site after the update is no longer in the fast database or it seems. In fact If I use some of the fast features to better understand what's happened I discovered that using the url.host feature there's no sign of my site even if using the link.all feature in Fast my site has 43 link. Have I been blocked for some reasons?
Might be for a lot of reasons. To make sure the site is not indexed any more I would look for specific text elements of the site. If the site does not come up you should search for the IP of the site. I think it's rare, but Fast has said they would in some cases ban whole servers.