A few days ago, I redeemed an iTunes gift card in the amount of $10, so that aftwr I redeemed it, I had a $10 credit. On the same device and with the same account, I then bought two albums for $9.99 each. I have received one purchase receipt for $10.77 billed entirely to my credit card, and in iTunes my account still shows a $10 credit. What is that credit still doing there, and why was it not applied to my purchases? Location is USA and my purchase consisted entirely of music.