Can't log in and use secondary e-mail

I am having a problem with setting up a secondary e-mail address. Sandy is saying that the e-mail address that I want to use is already in use and when I try to log in using that e-mail address, I have no password. I tried to have a forgot password e-mail sent to that e-mail address and I never received an e-mail and there are no e-mails in my junk folder. Is there a way to have that e-mail removed from the main account without being able to log in? The e-mail address is diane@greensplus.com
I am not sure why Sandy is even saying that the e-mail address has already been set up because I never regestered it-a client used that e-mail address as a reminder for a meeting. Could Sandy have captured the e-mail that way? Please help!