Welcome to IKEAFANS, jakeandrebecca.
To those of us with Adel Medium Brown kitchens, your story will sound all too vaguely familiar. Over the course of this year, the color of AMB pieces has changed, as IKEA has changed its sourcing for these materials.
The first thing you should do is check to see where and when your original finish pieces were made. What you are looking for are the supplier code and the manufacturing date. To do this, you need to find 2 sets of numbers - these will be either on the label of the boxes the pieces were shipped in, or on a small sticker somewhere on those pieces. On doors, the sticker may be inside one of the hinge holes; on the drawer fronts and cover panels, the sticker will be on the back side of those items. On your boxes, the numbers will be on the label.
The supplier code (SC) is a 5 digit number - this format doesn't vary, though the number does. Each supplier that produces goods for IKEA has a unique code - it might be 16230, 20995, 21277, or something completely different altogether.
The date code (DC) is a little different, and the formatting varies a little bit. The date code will start with a "0" (that's a zero, not the letter "o"), and at a minimum, will be 4 digits altogether. It may be 4 digits, followed by a - (dash) and a 5th digit. There is another format that escapes me right now, but it includes the initial 4 digit number.
A DC of 0845 indicates that the piece was made in the 45th week (45) of 2008 (08); 0912 would mean the 12th week of 2009, and so on. A DC of 0845-2 would mean the piece was made on the 2nd day (Tuesday, I guess) of the 45th week of 2008.
Once you find these numbers on the finish pieces you've already installed, compare those numbers to the ones on the boxes of the pieces you're trying to install now - chances are, they will be different.
Your "goal" is to find new boxes with DC and SC numbers that match your old pieces. This may not be an easy thing to do, as those old numbers may have been sold out, or your store folks may not cooperate. But the thing is to stick to it, scream a bit (ok, a lot, maybe), and climb the ladder to the store manager.
To get an idea of what others have faced, check out this thread, which tells the tale of the color changes in AMB.
Adel Medium Brown doors don't match
On a side note, what extension are you dialing to reach the after-sales department?