responsive columns not working Please help a guy out

Hello and thank you everyone for reading my query. I am stuck and trying so hard to complete my first website for a friend. I love learning this stuff but I am getting frustrated with a few things. Please help.

On my home page I am trying to get the three columns below the meta slider to drop underneath each other in responsive view. Presently they are scrollable to the right when you minimize the window, or view on a smaller device. Is there a way to hide them from responsive view?

site url:http://test.riverwalkpizzeria.com