You can backup your data at any time by doing a manual course backup, we have not stopped users from doing this.
If your site has 200mb of quota and you have a 100mb course, 1 backup of this course will put you close to your quota limit. If you had automatic backups on then you would be over quota after 2 automated backups and this is exactly what was happening to our users which prompted us to disable automatic backups.
At this time we are not able to offer additional storage space in our plans.
Our system already notifies you when you are close to or over your quota limit.
Refunds are considered on a case by case basis (as per our terms you agreed to), and you should submit a ticket via the Support tab in your MoodleCloud Portal in order to get this process started.