Can't access Desktop site or Dashboard

first of all, i am brand new WordPress.

i made a page a couple of days ago and today i tried adding a mobile plug-in for the site. https://www.changetofire.com

since i activated that new plugin (WP Mobile Express) i don’t know what i did but it’s only showing the mobile site. i want to deactivate the plugin but i can’t even see my normal WordPress page to access the Dashboard when i try going to /wp-admin.

i have no idea how to access anything to deactivate this thing!