Renewing / Upgrading your list
Automated reminder notices are emailed to list owners when the list is 30 days away from expiry. At the same time a "Renew now" link will appear next to the name of the list in your Account. Click on that link to complete the renewal of the list.
Follow-up reminders are sent again 7 days before expiry, then on the day, and finally one week after expiry date at which point the list is suspended. Suspended lists are kept for 30 days, then removed completely.
List owners can renew (and thereby reactivate) suspended lists during that 30 days via their Account.
Upgrading (increase the number of allowed subscribers)
If the number of subscribers on your list exceeds the permitted number an "Upgrade now" link will appear next to the list name in your Account. When the permitted number has been exceeded by more than 10%, automated notices are emailed to list owners each day. The owner can either upgrade the list or remove the excess subscribers.
When upgrading, the payment due is calculated from the "remaining time" at the higher rate, less the amount already paid for that time. After 7 days of notices if the list is still oversubscribed it is frozen until rectified.