[Aachen]

Or less hassle than completely moving over to a competitor (terrorists win in that case, to use counter strike terminology): add a backup MX record, perhaps to a small vps that just forwards mail to the real server with no retry timeout.

[throwaway984393]

It sounds like it could work.

Are there any mail admins in the comments who could propose an smtp daemon & configs that would store all mail for a domain and wait indefinitely to forward it on? I think there's a lot of users/businesses who would like to implement this.