I feel for you, I really do. It's such an amazing figure. i have had factory error problems with Robotkingdom orders (3rd party and official). RK has always been very cooperative when I have contacted them about these issues. I hope you have the same experience.
Thankfully, it looks like I was able to resolve this. Daniel at Robot Kingdom is going to send me a replacement arm. Not sure why they have extra parts around, but that is fine by me. Hopefully Ill have it sometime next week.
It definitely looks like a nice figure and Ill be happy to have it display with my other generations figures.