My email address at my hosted domain is like jsmith@jsmith.com, and I have a catchall so I can get mail for *@jsmith.com
Someone eventually bought jsmith.net for his business and now I get a lot of mail meant for jacob@jsmith.net sent to my jsmith.com domain.
Fortunately he uses just the one address and now I set up an autoforwarding rule to forward his jacob@ emails to him.