Amateur hour. Use all the excuses you want:
- The domain was due to expire and you didn't notice.
- Nobody checked to see if it had been renewed.
- You relied on your host to email you BEFORE the domain expired, and didn't notice when they didn't.
- You had incorrect contact information on your main business domain, or an incompetent DNS host.
- The email obviously went to SOMEONE, but you didn't bother to check who that would be on your domains, or have a catch-all.
Now think that I'm supposed to trust vital company infrastructure components to you, and you can't even manage a simple domain renewal without messing up.