FYI Preston. Since I changed to a different email address it has been perfect. Trying to change back (assuming maybe it was a fluke) it wouldn't even send me the confirmation email... finally got that sorted and switched back.
BUT... Now I just have a filter that forwards my emails from here back to the SAME email address I had such problems with (dr.com which is just a mail.com alias) and I have ZERO problems. They still show that they come from your email here. So I don't feel the problem lies on the mail.com servers... just maybe that your hosts mail servers must just HATE mail.com accounts/servers.
Anyway, my setup works just fine for me now... I just thought you might want as much insight as I could give you in case you have others with similar issues.