I would have simply refused delivery when it arrived at my doorstep, and then disputed the credit card charge if Apple attempted to bill me for it in the future.
Since you accepted delivery (or somebody else in your family did), then I'd keep it. Selling it for anything close to face value will end up ripping the buyer off in the end, unless you tell them up front that Apple has no record of the Serial number, and as such they will not be able to get an RMA for repairs in the event they're needed, nor will they likely be able to purchase AppleCare for it.
You could also try bringing it by your local Apple store or something ... maybe they can give you a store credit for it, or let you exchange it for something else (worth a shot, at any rate) ... provided you didn't open it yet.
Since you accepted delivery (or somebody else in your family did), then I'd keep it. Selling it for anything close to face value will end up ripping the buyer off in the end, unless you tell them up front that Apple has no record of the Serial number, and as such they will not be able to get an RMA for repairs in the event they're needed, nor will they likely be able to purchase AppleCare for it.
You could also try bringing it by your local Apple store or something ... maybe they can give you a store credit for it, or let you exchange it for something else (worth a shot, at any rate) ... provided you didn't open it yet.