Hey Derek,
I can't find my camera, I think I out-smarted myself putting it away so my son couldn't get to it, but I have a 500 round count box of XM193 left, and here's what is listed on the end of the box:

Federal Ammunition
XM193
5.56mm
Ball M193 55GR. MC-BT
Federal Rifle Cartridges
25 boxes of 20 500

Does the web site show that they also have the AE223? If so, they probably pulled the wrong stuff to fill the order and their inventory would reflect this. The problem lies on their end. I know nothing about this company, but they could've ordered the wrong junk in the first place and not caught it to begin with. Hopefully he'll buy it back from you.