My husband and I are trying to reach a company with a problem we are having. He has emailed from his job and I have emailed from home. We had been able to get emails from them but now every time we get a mailer daemon. This was in the one I got this morning..Does this mean that they have blocked us? Could they be so irritated with us that they have bloced our domain? (They are located overseas, so for them to replace and correct their error will cost them cash)

(religiousmall.com: domain at cox.net does not designate permitted sender hosts)