We had a test site that we were testing the billing for but we deleted the site and it is still billing for hosting.
Apparently, we turned off billing for the site and after that didn't work the site was deleted but money is still transferring for that site. I didn't do this myself and it was some time ago so I can only pass on what I was told.
I just updated the pro sites plugin from 3.1.3 to 3.2.2, I'm not sure if this fixed the problem or not as I would have to wait a month to test it (not something I really want to do).
This doesn't seem like a bug that slipped through so I suspect that I may have configured the plugin wrong, is anybody else experiencing the same problem or have some suggestions?