Macy's is notorious for having website glitches....It happens all too frequently. Just call the 1-800 number and order it that way because there's no telling how long it'll take them to fix the glitch....For 2 - 3 weeks in December, they added a lot of old eye shadows to their website. You could put a quantity in the box and click "add", but the item would not be added to your shopping cart. I called the 1-800 number about it and they told me they were having problems with the site.
.....So this sounds like the same thing is happening.