One thing, after re-reading your post, I wanted to add that $15 only covers 6 months of fixed service-that is the Fixed plan, with Two Pop Ups per IP# per 12 hours. So if you were on that plan let me know as I set you on Variable which is no pop ups and if you go over a certain bandwidth limit you pay for the bandwidth used. I didn't look at the usage on your board, but if you have viewed the View Bandwidth screen then you might have an idea of what kind of credit the board was 'actually using'. If you need to be put on the Fixed plan let us know.
Also it might revert in the morning as I did the upgrade manually so I will try to remember to check it when I log in to see if it did indeed revert again. If so I will ask BbBoy to see if he can take a look at things, because it does have credit left.