Wendy told you what to do; and didn't need to "respond" again...imo. Creating a need for a response does not mean a response is necessary. You stated you didn't know of any cooling packs that last two days. A legitimate customer would have shipped back priority express and swallowed any extra just to resolve the issue and make it go away. But this is only MY opinion, and I could be wrong because I know absolutely nothing about shipping roaches.
I do, however, understand Customer Service and all its disguises. In this situation YOU kept the issue going. Once Wendy (and knowing her reputation) gave you her directions, you should have proceeded with all haste to rid yourself of the complication. You didn't, you gave excuses, flimsy excuses, imo.