Spam

Periodically, my business email starts getting spam from known email addresses - people I have been in contact with for various reasons in the past. Recently, I have been somewhat disturbed to see the spam from support@kbiherp.com. It is bothersome because I don't like the idea of spam going out to my customers/associates with my business name attached; and also because I did not create that email address. I do not HAVE an account with the name "support".
Any suggestions on the best way to address this? I'd rather be proactive than to have people blocking my email account due to spam.
I have used a dummy account to send an email to support@kbiherp.com, and (as expected) it bounced back because there is no such account; so I'm not sure if there is anything I can do about this. (If there had been such an account, I could have attempted to delete it, or addressed it with my server)

I had a similar problem but my actual email was used. Luckily nothing embarrassing. I did some research and I came up with changing my password. This did take care of the problem for me. Maybe check with your email administrator, check settings to make sure nothing was changed. Just some ideas if you already haven't tried.

I'm not sure if there's much you can do about it. E-mail spoofing is fairly simple and it has nothing to do with your domain.

For instance it would be pretty simple to send emails as "God@MyOwnLittleUniverse.com", and on the surface it would look legit. Whether or not that domain exists is irrelevant.

I don't know how to fix it, but I've gotten Spam/scam emails from friends' email accounts occasionally too. Not that long ago I got emails that appeared to be from 2 different friends' accounts. Both emails said they were robbed in London and needed people to send money to help them get home. Neither of them were robbed or in London, so I'm assuming this was some sort of scam and if I had sent money it wouldn't have gone to them.