.htaccess file being overwritten

Anyone else have this problem or some up with a solution? I invest so much time rewriting the rules and something overwrites them. My web host says it is not something they are doing.

Here is my modified file:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^advice(/?)$ category/advice [R=301,L]
RewriteRule ^best_of_occams_razor(/?)$ category/best-of-occams-razor [R=301,L]
RewriteRule ^history(/?)$ category/history [R=301,L]
RewriteRule ^life_2003(/?)$ category/life-2003 [R=301,L]
RewriteRule ^life_2004(/?)$ category/life-2004 [R=301,L]
RewriteRule ^life_2005(/?)$ category/life-2005 [R=301,L]
RewriteRule ^life_2006(/?)$ category/life-2006 [R=301,L]
RewriteRule ^life_2007(/?)$ category/life-2006 [R=301,L]
RewriteRule ^metaphysics(/?)$ category/metaphysics [R=301,L]
RewriteRule ^philosophy(/?)$ category/philosophy [R=301,L]
RewriteRule ^politics_2003(/?)$ category/politics-2003 [R=301,L]
RewriteRule ^politics_2004(/?)$ category/politics-2004 [R=301,L]
RewriteRule ^politics_2005(/?)$ category/politics-2005 [R=301,L]
RewriteRule ^politics_2006(/?)$ category/politics-2006 [R=301,L]
RewriteRule ^politics_2007(/?)$ category/politics-2006 [R=301,L]
RewriteRule ^sociology(/?)$ category/sociology [R=301,L]
RewriteRule ^technology(/?)$ category/technology [R=301,L]
RewriteRule ^the_arts(/?)$ category/the-arts [R=301,L]
RewriteRule ^atom.xml$ wp-atom.php [R=301,L]
RewriteRule ^index.xml$ wp-rss2.php [R=301,L]
RewriteRule ^index.rdf$ wp-rss.php [R=301,L]
RewriteBase /wordpress/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /wordpress/index.php [L]
</IfModule>

# END WordPress

I can set a cron to copy over the file periodically but that doesn’t solve the problem.