My card had expired in February and I could not renew Membership in WPMU DEV. We resolved the issue almost immediately via email.
From chat I was inform that:
The only thing that turns off monitoring is when a site is logged out of hub, or membership expires
Membership was renewed in something like 24 hours. This is normal in business. Your setup should allow for a grace period of at least a couple of days if the charge does not go through.
Now I have to go through and set everything up again.
Not user friendly at all. Also, I can not just select the sites I want and turn on Uptime Notifications for all of them at once. Have to do it manually.
Plus, your system needs a feature to notify for a database connection error like the one I had. I realize the site is technically "up" but you should be able to determine if there is an issue like this. These are needed features.
Don't get me wrong, the support I've gotten for WP issues from WPMUdev has been GREAT, but Hub and the tools seem really to be lacking in function.