(PAID) SEO Help Needed! Duplicate Meta Tags, URL's, ect

[caino]

We have been running a pretty heavily customized Xenforo site and we are having some issue's. One would be Duplicate Meta Tags, Our URL has duplicated or something.. www.YourSite.com / YourSite.com
Also we need some help with our mobile, Google seems to think we have major HTML errors.

SOMEONE PLEAAASE HELP!