I think it's more likely that he isn't going to return the item at all, thinks "the man" is trying to stick him with something he doesn't like, and wanted to vent upon someone who couldn't fight back for this and other injustices and frustrations in his sad, little life.
Working in the cable industry, I get these all the time. On top of the fact that in the grand scheme of things the cable company is only slightly more popular than Exxon, customers know that when they call in, the person on the other end of the phone is rarely allowed to defend themselves and must put up with whatever abuse is doled out. These customers only use the problem they're calling about as an excuse to unload all their frustrations so they feel better. After all, the voice on the other end of the phone doesn't belong to an actual human being with feelings too, does it? They also never actually want anything to be fixed, because if it were they might lose the excuse they have to whine and moan.
Personally, I'm getting to the point where I despise this type of customer. I have no, and I repeat no, problem with a customer getting upset when they have clearly been wronged (like by being overcharged or disconnected in error), but I do have a problem with people who call specifically to get an attitude. Ironically, with this customer, it doesn't matter what's done or what you say. Even when you tell them precisely what they want to hear, they will still yell and scream about that. How do I know? I've had this type of customer tell me that they will only accept a certain solution to the problem, and when I confirm that's exactly what they'll get (you know, exactly what they asked for), they continue to yell and complain. They yell and complain because I did exactly what they wanted me to do. How DARE I listen to my customers and respond to their needs!
...don't you know the first law of physics? "Anything that's fun costs at least $8.00."