WordPress Mobile Response not activating

My site is responsive because I paid for a premium theme that is responsive. I have a custom home page and when I change the browser size, it works great.

However, when I try to view my site on a mobile device, it just goes to the regular old wordpress template and doesn’t show the theme I bought.

Is there a plugin I should be using to over-ride going to the standard wordpress template? Or do I need to override with css? If so, how?

here is my website: http://www.vittlewise.com