site was verified, now is not?

Hi , my site http://www.milanclothing.com was verified and the sitemaps
were working fine, then when I logged into my sitemaps account today,
the system says that my site is not verified, even though it has been
verified and working for the past month, do you need to reverify your
site every so often, or is this a result of some system upgrade? Anyone
else have this problem?

Cheers,

Myke Black
http://www.milanclothing.com (Still on PR0!)