> Again at the bottom of every page of the site
> includes that we hold the copyright to the site. 
> Can you please assist in this matter.

In that case the best approach is to ask a lawyer, who will probably advise
you to send a DMCA notice to the site's owner (if in the USA)

HTTrack is a free software tool, aimed for archiving, backup, and personal
use, and unfortunately there is no way to prevent this kind of abuses.