First off I'm on Zavvis side sympathetically, but not from a legal or business stand point. None of these customers asked for or expected to receive this merchandise. The problem was an internal one and the fault lies directly at the feet of whomever inside Zavvi made this balls up. These customers just made a purchase in good faith and were given more than they asked for.
Now I see nothing wrong with Zavvi asking these people to send the Vitas back out of the kindness of their hearts. But threatening legal action against what were until Zavvi's own fuck up, quite honest and happy customers is not only foolish, but is public relations suicide. It makes Zavvi look doubly incompetent. Not only are they stupid enough to just accidentally give people an expensive item they never asked for, but now they are deflecting the blame to innocent customers who didn't cause this mess in the first place. And if they actually do try to sue these customers to get the Vitas back, they are just throwing good money after bad, with no guarantee they will reap any benefit, as I'm sure good legal solicitation is going to run way more per case that the price of a fucking Vita. With I might add the added benefit of shooting customer good will in the foot. As would you ever buy something from these clowns again if you found yourself in this predicament? Hell, would ever buy something from them at all knowing they were this incompetent?
Oh well. I'd say their best move would have been to win positive PR by eating the loss, letting the customers keep the Vitas, announcing their generosity publicly, and riding the wave of positive PR to victory during the Xmas sales season.
Oh and firing the shit out of whatever bozo just cost them thousands of dollars.