Building on Jonathan’s example, I would create a separate template for company post archives. Then you would just change the get_template_part function call to get_template_part( ‘content’,’company-posts’ ); or similar, and skip the “if($_GET)” validation stuff.
A bit strange you’re being directed to ../companies/ if your post-type slug is ‘company’ since archives aren’t automatically pluralized.
Lastly, what error are you getting?
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