I had this problem in June. And now it's doing it again. I went to a local "genius bar" and they were super helpful - but also perplexed. Obviously not a commonly reported problem. It was quite the process but I walked out with lots of room in my iCloud! I'm going to make an appt again and ask for step-by-step instructionsthe problem was resolved. If its happened twice, I'm sure it's going to happen again!