Hello,
No, I don't believe that my email address had ever been used by any other person.
This problem occurred when I inadvertently typed in the other person's email address in the mail forwarding option section. I do email this person on a regular basis. However, I did not intend to forward all of my inbox mailings to her!
The issue has now been resolved; and, as a result, I have a much greater understanding of roadrunner settings.
Thanks again for your help!
clouise22