There are real issues such as "the grey market" where cameras are imported and you end up with no warranty. That's not a Samsung issue but as we move on we all hope the days of warranty issues across borders to improve.
WHY THIS IS takes a short course in how the world legal systems work and much more. But the grey market items could explain why the s/n is no good.
But let's get back to this "RECENTLY BOUGHT." Most stores will swap out or accept returns if the product is dead or bad right out of the box.
I have recently bought a TL350 camera which has some issues with yellow tinting and I want to get it serviced under Samsung's warranty. I have NEVER been treated so poorly by any person or organization as I have by Samsung. I have spent hours on the phone trying to get a this issue resolved. I even had one rep in executive cs put me on hold and leave work! The last rep tells me that the s/n o my cam is not valid and will not honor the warranty. I don't understand how these people can be so unprofessional and work for such a large company. I know I talked to at least 10 different reps over the last five days. So, if you chance to buy a Samsung product, I hope it works perfectly so that you don't have to experience what I have gone through. $300 out the door.