But recently, this developer we are working with, has come into the habit of responding to emails too late (which lag the projects and hurt our client relations). When inquired, he claims that he had already delivered the email and chances are that I missed it because of possible technical reasons. And he sends in the email again (2-3 days late). This has already happened 4 times during past 3 weeks. Is there any way to verify if he is being honest?
In short, I would like to know if there is a way to verify false email delivery claims.