need help locateing date and location of emails
 

I am in a legal dispute with a con man who is stating that he sent me an
email changing the terms of our contract. He turned in an email to the
arbitrator (altered) that said he sent it to me in Jan 20 2007 changing our
contract terms. This never happened I would never have accepted it. The
arbitrator ruled that he must prove he sent it and I received it. Three
months later he comes in with a read receipt saying I opened it 15 hours
later. Both of these were printed out and no one has seen the actual emails
he is stating he has. I have requested a subpoena to look at his computer to
see these. His ISP is Comcast and he uses outlook. He stated in his reply
that Comcast sent him a read receipt showing I opened this email.

How can I prove these were never sent or the read receipt was sent????