Double promo credit was just their mix up, is my guess, it's happened to me on other orders in the past.
They never sent me the DLC Psyco Pack, I think I would have been less upset about the missing $10 credit, versus the missing DLC. Now I am playing the waiting game for CS to get back to me to make it right.
On another note, I had a couple of laggy matches, but also had some great matches. And a couple fantastic matches, when the opposing team thought they were playing FFA in COD, lol.