We did some quick testing --
we confirmed that vxreize does does not automatically create a vxtask for tracking. You'd need to supply a -t task tag -- see
http://sfdoccentral.symantec.com/sf/5.0MP3/solaris/manpages/vxvm/man1m/vxresize.html
It also took some time -- an hour or two -- as VxFS had to move all data that is in the region to be shrunk into any free space in the region that will remain post-shrink. Three days seems long, but since we couldn't recreate your scenario, I can't give much more of a recommendation than to use the -t task next time.
In terms of confirming the current size of the file system and volume, the file system metadata and volume metadata will have that, but I would sugggest working with support to gather than information.