Modification to existing website - debug - EMERGENCY FIX

I have an existing website located at [login to view URL] It is a dynamic (responsive site) made in HTML5 / CSS3 I had paid a coder to do the work, however he wasn't able to fix a bug in the main header. I need several things fixed/patched/corrected: 1) most importantly: the boxes that show up on the main header (mast) seem to all show up at the same time when viewed from certain mobile devices. Obviously ... this isn't good as they are supposed to show seperate messages (there are 4 currently). I'd like this mast header debugged for mobile versions as well as the standard web browsers (IE, Chrome, FF, etc) ... I don't know of any problems with web browsers to date, I'd just like this verified and to be done (properly). 2) the background images on the same mast header seem to "move around" a little depending on the resolution of the computer being used (ie - it looks a little different on the laptop im using now which is 1920x1080 versus my old laptop at 1366x768. It seems the top of the image is being cut off, or something. I would like the image to be configured to where it displays in a similar fashion on any browser. I don't care how this is done AS LONG AS: mobile functionality is retained, and of course, cross browser compatibility is retained as well and the site remains responsive as a whole. If I need to resize images to help with this, I can try to provide assistance... but selected coder will be responsible for end result on this project.