i don't think its correlated to the one u actually have linked to your xbox, although im not sure, but i doubt microsoft would just give it to you for free, either they charged the card u originally had, and the automated system didn't catch onto it yet, or there was a mistake made that they will catch on to, if you aren't worried about being charged on an expired card which you think down the road if the bill ever caught up with you that you might be able to dispute, i say rock on and ride it out, otherwise i would just leave it alone and see if it fixes itself or you truely slipped through the cracks, but i think its just a mistake, or the old CC you used was charged and it hasn't been corrected yet