Item On Sale Less Than 24 Hrs After Purchase

I purchased a Cubeicle (9 openings) and the fabric bins on Saturday 1/19/13 in the afternoon.  I put the purchase on my Target card and went home.  Sunday morning I got my paper and saw the Target ad and found the Cubeicle unit I bought for $51.99 was on sale for $39.99.  Is there any price adjustment that can be made to my Target account?  I realize that shopping on Friday or Saturday is a risk.....because what if it goes on sale on Sunday?  But it wouldn't work very well if no one shopped over the weekend until after they checked out Sunday's ad.  Target would not be very busy on Saturday!   I have already taken the item out of the box - I have begun to put in together.  I could take it apart and put it back in the box (and return it) - but as you can imagine it's a heavy item and that's not as easy as it sounds.