A well worded email to Northern Tools corporate office can work wonders. (and seems to have already in your case.) Corporate offices really like to take care of customers, when the lower branches of the business fail. It gives them a rush to display their corporate power over the warehouse, customer service, etc.
Ask me how I know.
(I never fail to complain when something isn't correct, or damaged when shipped. Everyone works hard for their respective money, and expect to receive what they pay for. I could write volumes about my victories over the last few years, but that would be gloating.)
-aaron c.
By the way, that looks like a nice little MIG. Let us know how it works for you. If that little grinder is the one with the 2 x 27 belt, those may be harder to find, seems like an odd size. Grizzly sells them though from 80 grit to 220 grit pretty reasonable. You might have to do some searching around for that size.