I was paying $11.99 for 2 TBs, but have been getting notices that my storage is almost full, and that I should upgrade to 3 TBs. I also noticed that while every month since signing up, Dropbox has been taking the monthly payment from my card, but for September, they didn't. I checked on the upgrade and saw that it would be for 2 TBs, maybe 3, but the monthly payment would be the same. I'm a little confused by all this. Can someone help me figure out what's going on?