FWIW, it could be an Amazons fault. Someone bought the monitor, used it, decided they didn't want it and returned it. The seller looked at it, decided it looked good enough, and put it back in his inventory at Amazon as new.
You'd have no way of knowing. People used to (maybe still do?) buy expensive graphic cards, take them out and put back a cheap one with a flashed ROM. Then shrink-wrap the box again and return it.
You wouldn't blame the manufacturer in that case. I never buy expensive things from Amazon because you can never trust what you're going to get, especially with inventory comingling.
If you bought directly from the Dell website, I'd share more of your anger. I also dislike Dell in general though, so I wouldn't buy their stuff anyway.