Kudos to @da_collecta for keeping things positive, but yeah, I'd be a little annoyed. Maybe very annoyed.
I have to imagine the demand for the Kmart mail-in Datsun 510 maybe higher than any mail-in before it, and there has been concern that Mattel was prepared for it. I have no reason to think they are not, but when someone opens a box expecting Datsuns and it is full of the upcoming Walmart mail-in Toyota, that would be the concern.
Apparently it was a mixup. Mattel uses the same distribution system for all mail-ins, and things got messed up. And more than a few of you have gotten the Toyotas instead. I have two coming, so we will see what I open. (Maybe I will do it on Facebook Live.)
Nonetheless, Mattel has said they will correct it. I am not speaking for Mattel by any means, but those who have called have been told that they will send out a shipping label to shop the Toyotas back, and they will replace them with the Datsun. Annoying to be sure, but at least the problem is being corrected.
So don't fret. But grumble a bit, because you should. This mixup isn't cool. But your Datsuns will arrive. Eventually.