We are sorry to know of your issue and your subsequent departure.
That said, we would like to clarify that an invoice is sent 5 days before it is due. On the day that it is due to be charged, another email will be sent to let the clients know if the charge is successful or otherwise. If it fails, it will continue to be retried once every week and a notification of the charge outcome will be sent. Failure outcomes caused by credit card expiry will be notified in these emails.
On top of that, for expired credit cards, there is also an email notifying clients sent weekly.
We have verified that our systems are working fine. That said, in this current age of spam, it is possible our emails may somehow not reach the intended mailboxes.
This is the reason that we typically give a client a grace period after the bills are due. This grace period is not fixed, but we have been known to give a few weeks. Unlike other places, we actually do not automatically suspend an account once it is in default.
Unfortunately, despite all our best efforts as detailed above, it may seem to have been insufficient.