I'm sorry that happened. I've had similar and worse experiences. I recently bought and had to return a blue camo v3 Tamagotchi. The seller stated the condition to be "good." When i got it, the back wasn't the original battery cover, there was food gunk inside the unit and under the cover, and the Tama wouldn't stay on with a new battery. After much hassle, i finally was able to return it--at first i wasn't even going to get my shipping refunded, but did when i pressed the issue, saying what the seller did was basically fraudulent by listing something and being false in the listing, so then I was able to get reimbursed that was well. Lo and behold, the guy relisted the Tamagotchi, and all he did was add "Good and has a pink back cover." So if you see that listing, beware, that Tamagotchi doesn't work and is in poor shape. I managed to get lucky and got an identical one from another seller at about the same price and it looks practically new.
Thing is, looking for it, I don't even see it up now, so I think some poor soul ended up buying it. I feel sorry for this person who will get it now.
I've also gotten Tamagotchi/virtual pet lots where pets haven't worked or were broken in some way, but then again that's the risk you take. I managed to get some of them working, which was good. The others I keep around for spare parts, and they've come in handy.