This is getting a lot more interest than I expected, so I’ll just let you know that:
- After a lot of to-and-fro with customer support, I spoke to a director at the company.
- The director disavowed any wrongdoing on FastMail’s part.
- I received a full refund, even though I used the service for two months.
- I stand by what I said about their customer support.
This is now resolved. I am self-hosting my mail, finally. There will be no further discussion on this topic.