I'm sorry to hear that you had this experience.
This issue is known as clouding, and can happen a number of ways.
The most common way is that the brightness setting is too high. Most people find that if they adjust the television (calibrate it, so to speak) for good colors, that issue usually corrects itself. Some "clouding" is a possibility with LCD - however, it shouldn't be so much that it bothers you.
That said, I read that you did try to adjust it to no avail. I'm sorry our service center didn't get back to you. If you'd like to post some pictures and your service ticket number, I would be happy to escalate this issue and find out why you haven't received a call back. Your service ticket should start with a 4001xxxxx 4002xxxxxx or 2001xxxxx number.
I hesitate in stepping in the middle of some service issues, but if you haven't been served with proper results, you deserve to be. It could be that they've ordered parts for you already, but let's find out.
I recently purchased a Samsung LN52A630 TV, and on dark scenes, or especially the black areas above and below a 2.35:1 aspect ratio film on blu-ray, there are brighter areas in the corners of the screen.
I called 1-800-SAMSUNG and Samsung promptly dispatched a local TV repair person, who didn't know what to make of the problem (and used no testing gear); they said the set 'may just be that way'. I answered the survey e-mailed to me by Samsung the next day (very punctual) and asked for an e-mail address for someone I could send pictures of the problem to, but I have heard no response. This was almost 2 weeks ago.
The bright corner areas are not as noticeable in a bright environment (daytime), but very noticeable at night, even with lamps on in the room, most noticeable in an unlit environment. I have used all 3 modes (dynamic, movie and standard), and even have decreased the level of the backlight, but the bright areas in the corners are still present, albeit dimmer, but then again, the entire image is dimmer, not just the bright spots.
My question is: What are Samsung's specs for black/brightness level across a 52" screen, and does my set meet those specifications?
I can take a picture of the set this evening if you would like (and all the picture settings corresponding to the image), and link it to a post if that would help...Considering the glowing reviews these sets get in Consumer Reports and other places, I was expecting more than what I got...