500 Internal Server Error

I broke the back end of a website I just got access to – vandenbergspousesclub.org

I just upgraded everything on the back end of the site (wp, themes, plugins), and it was working fine. Then I changed the theme to Dara, made a few customizations to the menus, and that all seemed to go ok. The wp dashboard said I needed to install jetpack to have something work, the testimonials I think it was, so I tried to do that and that’s when my /wp-admin started throwing the 500 error.

So then I try to login via my wp account to access the support forums. Now under my sites option, the VSC site showed up with my other urls but said it couldn’t connect, so I disconnected it from my wordpress account. The 500 error remains on the backend.
I assume jetpack is still active on my install, but I can’t get back to the dashboard to uninstall it.

Please help me fix this.