Well usually I find a way to find out exactly which set they want and what they already have so I don't buy it a second time but it happens. And then I explain that even Santa snd the Easter Bunny can't get it right all the time. They can always exchange it for something they like better.
" I object to violence because when it appears to do good, the good is only temporary; the evil it does is permanent." Mahatma Gandhi
"This is the ultimate weakness of violence: It multiplies evil and violence in the universe. It doesn't solve any problems." Martin Luther King, Jr.