You will need to use mod_rewrite
instead to strip out existing query string:
RewriteEngine On
RewriteRule ^user/testimonials/?$ http://thesitedomain.com/testimonials? [L,NC,R=301]
RewriteRule ^user/contact/?$ http://thesitedomain.com/contact? [L,NC,R=301]
Take note of trailing ?
in target that strips out existing query string.