Paid subscriptions don't automatically expire?

[romojap]

I've tried searching for this problem, but no luck... I'm using version 3.6.1

I'm having a problem with my paid subscriptions. They are for a length of one year. When I go to AdminCP > Paid Subscriptions > Subscription Manager, I see x number of "active" subs and x number of "completed" subs. When I click on the number below the "active" tab, it tells me which users currently have active subs, along with their sub start-finish dates.

Herein lies my problem... Many users have finish dates which are long past due. Why is vbulletin reporting their sub as still being active? I can manually revert each user until the next sub, but this will become an increasingly tedious task as my board grows. I'd like to be able to trust vbulletin to do this for me.

Insterestingly, it did do it for me, for 3 users. But the rest that have not renewed subs are on a free ride.

--------------- Added at 13:16 ---------------

Ugh... bit the bullet, and went down the list, manually deactivating those subscriptions which have expired. However, vBulletin did not revert their usergroup. They're still on a free ride.

Is my vbulletin broken, or is it me that's broken?