Assuming it's a defect and not just assembled incorrectly, I'd just align it myself and drill new holes for the screws/bolts that hold it to the frame.  Yeah there's principle and all, but it would take me 5-10 minutes of time to fix vs. a lot of time + gas to return it.
Edit: I don't own a workmate.  Unless I'm missing something, it doesn't seem like it would affect functionality at all.  It seems purely cosmetic.