Need help fixing responsive site

After talking to @Michelle Shull. I bought this template as being responsive. Unfortunately not much help has been given from the developer (BUY SHOP Theme).
My website (www.ummust.com) does not work in computers when I enable the responsive markup. It works fine in Phones and tablets but not in computer. All images are small an not aligned.
If I turn off the responsive markup it works ok in computers but in phones revolution slider does not fit the screen and its not user friendly.
Can someone help me? Enclosed print screens.
Thanks
Teresa