I presume you're talking about one of the Samsung Nooks.
Who did you send it to?
When you registered it did you have to enter your B&N account information, on a screen that said Barnes and Noble?
The registration process on the Samsung Galaxy Tab Nooks barring device naming and wifi configuration and just getting down to what services you're asked to login to
Google account prompt - Drop Box account prompt - Samsung account prompt (the drop box and samsung may be in reverse order I'm going from memory), and finally Barnes and Noble account which should be required unlike the previous services.
I suspect you may have contacted Samsung and returned the device to them, they then processed it as a Galaxy Tab (whatever model 4 or 10.1) and replaced it with the same model in essence but with different software built in.
If that's the case I'm not sure what can be done, you may try contacting Samsung to see if they can track the issue.
This of course all hinges on the idea that you went through Samsung and not through Barnes and Noble, the primary reason I suspect this was the case is because the standard course of action for B&N is to just send a replacement device to you and have you mail your defective device to them after you've received the replacement.
As a reminder this is a user forum, so the above is nothing official.