Considering the order was placed on July 22nd, which is less than 2 weeks ago, you sure have a lot of built up anger over a mistake.
They deleted your post because your post was outright rude and disrespectful, not because they're covering anything up. If anything, dealing with your issue would probably get sat on for an extra day or 2 because of what you posted on facebook. Everyone makes mistakes. Maybe checker #2 was distracted for a moment and failed to confirm the missing ironhide hands before ticking it off. Maybe he got a call saying his wife was in labour so he scribbled some stuff on the paper, handballed it and left work in a rush. You cant judge without knowledge. If you bought a pair of size 10 shoes in store, and the person accidentally put 10.5 shoes in there, would you go back in store and yell and swear and call the staff monkeys and demand the right size, and STILL expect to be treated nicely? Because that's what you did, behind the safety of your keyboard.
Also, why the hell did you post a complaint to facebook without hearing from them first? What if a second box appears in the mail today or tomorrow, or hell even Friday with the remainder of your order, and they did that because it somehow worked out cheaper for them to post that way? Let me guess, you'd probably still complain that they didn't notify you that they were splitting the order into two shipments.
I feel sorry for people who have to suffer your imprudence.
I'll disclaimer this by saying I've never ordered from them or any US toy collector store - my strongish words are more a bewilderment of this scenario being a thing.