Stressed out pomegranate?

So I ordered a baby tree from an Amazon seller I'd had good luck with in the past. Except this time, the product I got looked nothing like the product picture. Instead of a young leafy sapling, I got a single twig with barely 6 leaves to it. I also live in the desert btw. So when the package arrived, it was extremely hot and humid within! I hurriedly took it inside and tested the soil, found it to be dry, and gave it q moderate cool drink. Just enough to soak the soul, and I let most drain out of the pot. Within a day, it dropped three of it's older leaves. I left it alone, and when I checked it again th next day it lost it's three remaining young leaves! Did I cause this? Was it the sellers fault? The weather? Should I wait to reorder until the fall when it's cooler? Can I still save my tree or is it too late? Help... Also, it's the "wonderful" variety and it looks to be maybe a few months old. Not even a year.

With a pomegranate, I would wait and see what it does. Yes, if you need to reorder I would wait until cooler weather.
It doesn't sound like it was your fault, with mail order it is always a gamble. But plants are tough and will often handle a surprising amount of abuse.