say little about the stand or its ability to swivel or not, there are a few things you might want to check first.
Make sure you are inserting the stand properly, most of the Samsungs have a slit on the bottom of the tv which the stands slips up into before you screw it in.
Have you assembled the stand at all? The swivel works with the weight of the tv, it will not swivel at all until that weight is on it.
I recently bought a Samsung UN32D4000. Having owned a Samsung LCD before I was under the impression that all Samsung LCDs/LEDs had an swivel stand, which I now realize they have not. Is there a replacement stand for my TV which actually allows me to swivel it?