About 3 months ago we switched to Google Apps from a terrible webmail application provided by our web host. We have since been told by a customer that he sent a cancellation email that we never received. Is there any way to determine if the message was ever received by Google and was subsequently deleted or if it never arrived in the first place? There is a debate over whether this message was in fact sent due to other events that have taken place.
The best answer to this question is No. Typically you'll only be able to get a mail server admin to trace a message if you can provide message headers. Without an email, you can't provide those, so he would pretty much have to sift through endless logs and spend in inordinate amount of time that he would consider a waste. Even with the headers, it can be a lot of work. So really, no, you're not likely going to be able to do that. Did you check the spam/junk mail folder?