Not without possibly voiding your warranty. How recently did you buy it? If it's been only a few days, you should be able to talk them into paying your shipping.
If you still don't want the hassle, then you'd need to crack open the case and see what's causing it to be misaligned. Check if the motherboard is screwed into the proper holes, if it's screwed in tightly, if any of the standoffs are bent or if there weren't any standoffs used.
Really, the whole point of buying a prebuilt is that you don't have to deal with this kind of crap yourself. What's the point in paying through the nose for a warranty if you aren't going to use it?