I had an issue with the credit card used to renew a Fastmail account. Fastmail sent me emails about the issue, but it took a couple days to fix everything on my end. Even after the renew date passed my email functioned as normal, so there seems to be, at least, a grace period. Not sure what would have happened if it went on for longer though.

>Not sure what would have happened if it went on for longer though.

When I missed the payment they sent me this:

"You can still use your account for now. If the subscription is not renewed soon, sending and receiving email will be disabled. If the subscription is still not renewed after a few weeks, access will be disabled. Eventually, the entire account will be deleted, including all stored messages."

Specific timelines would be nice to know, but otherwise this sounds reasonable. If you stop paying, you have a grace period to download all of the messages before they stop you from using their service as a read-only archive. Then you have another grace period to pay before they clear out your data so they're not wasting space holding onto your junk and to avoid maintaining any liabilities that come with having your data stored on their servers.

This is why paying for your own domain is so important. I keep mine prepaid for multiple years and my registrar sends me at least 5 emails before I would ever be at risk of losing it. My email address won't be getting reused until either emails are no longer relevant or I'm dead.