This is odd, indeed.
I'm on Macs; Safari and IE both go nowhere when clicking on "add pair to cart" or "add single to cart," for ANY bookshelf. Throughout the site, some items I could successfully add to cart (FM Brackets, Epic Grand Master 175 -- I wish -- some I could not (bookshelfs, towers).
Java/javascript enabled on these browsers.
Of course when I opened Mozilla, I was able to successfully place the order. So I'm looking forward ... (hope it ships today?)
Maybe sometime I'll call y'all just to show I'm not "anti-phone"