It looks like you started your account on the 29th of X month. The way the entire system works is based around your subscription date. So your downloads renew every month on the 29th (or closest date). Did you by chance download 2 PDFs at the end of November not realizing that was your next month’s quota? Would it help if we explained this during the subscription process to new users? The last thing we want to do is confuse people. Perhaps posting this under the “Subscriber Downloads” area would help?
Let me know what I can do to remedy this for you and feel free to also PM me or email via the CONTACT link in the top menu.