I spent the morning on the phone with my email provider and things are becoming a bit more clear. It seems after going through all the server logs my emails have been firing off normally- leaving my server and arriving to their correct destinations at which point we can no longer see what happens. So- after lots of educated conjecture, we can assume that my email is being flagged by spam filters (I was told these filters are "dynamic and constantly changing" sometimes updating themselves multiple times a day- really?! So I was told). So these lost emails went into the "black hole" filtered out by spam filters- that's why they're not in junk mail and neither myself or the recipients are getting notices of they're not being received.
So what can we do? I have all the log info on each of the lost emails I currently know of- so anyone having this problem has two options. Unfortunately I can't do any of this for you- as your email provider won't talk to me, and I can't get into your email for you...
Option 1) you can call your email provider and send them all the log info (that's all the number codes that are unique to each and every email) and discuss with them how to fix the problem. This could be quite a feat with larger companies like Verizon or Earthlink (the two main culprits in this case)- but it can be done.
Option 2) You can log onto your mail account and try to modify your spam filters. You may have something called a "white list" where you could add my email address- or you can try to lessen the filters so more mail gets through to you without falling into the dreaded "black hole".
Wow- that's a lot of info- but it's been a very informative morning. Feel free to email me with any questions (I'm getting them!)- I'm happy to work with you anyway I can to figure all this out... frustrating but kind-of interesting. I guess it proves that all my paranoia that emails get lost wasn't totally unfounded. sigh.