I have had a Xamarin University subscription since May and have taken several classes, both live and self guided. Yesterday when I logged in to download the course materials for XAM312 I discovered that my account had been reverted to a trial subscription. I was still able to take the course, and my future course registrations still showed up, but I could not download the materials. This morning I have discovered that all of my future course registrations have been cancelled. I sent an email yesterday to email@example.com but have not received any reply. What has happened to my account?