Relax man. I am very sorry your chain is being jerked around by some hr department, but if it is one thing I learned in my time in the commercial world, it is that hr isnt to be trusted. I know that isn't what you want to hear, but it is the truth. The people on this forum arent the ones jerking you around, and I recommend you don't take your frustration out on them. Like someone mentioned, reflect on your interview, as that is where something went wrong.
Good luck and Merry Christmas.