I order a lot from them. Have for many years. Recently, I punched in the search term "7x57 Mauser," and several results popped up. I searched for the cheapest and clicked, then went through the finalization process. Today, two boxes of 6.5x57 Mauser arrived, not 7x57 Mauser. I checked my order history, and indeed, that's what I appear to have ordered. Now, sure, I should have looked more carefully at what popped up on my search for 7x57 Mauser before clicking, so there's that, but when I called and explained that this purchase option popped up on a search for 7x57 Mauser, they should have agreed to accept it in return, but refused, due to policy on ammo. So I was forced to eat the loss. I guess I understand the reason for the policy, but still not thrilled.
Would you go into a restaurant and place an order, and then when it came to the table, tell them you had changed your mind and wanted something different and expect not to pay for the first meal you ordered?
Sounds to me like Midway shipped you exactly what you ordered.
