I can see that you are frustrated, but a companies ability to quickly ship a product and not respond within a few hours to your mistaken order is not their problem. Granted, they should probably have a better process in place or someone that can address these concerns quickly.... But you should have been sure that you wanted it prior to placing the order. That guy's voicemail you were transferred to, he probably does a lot more than just respond to voicemails about people who change their orders. I am sure he probably does quite a bit. Next time be sure what you want, and don't throw a fit like some bitchy customer does. They are a business, they have lots to do.
I work in customer service, and people like you sir, are a pain in my ass.