Marc
Emails don't require a signature. Also, a professional email address should show your full name instead of just an email address in the "From" field. For example, if I received an email from you it should show From: "Marc W.D. Tyrell, PhD". You shouldn't have put "Marc" above your full name and title at the end of the email. The end of your email should only indicate your full name, title, and contact information. The response you received was wrong as well. Especially, from an education organization.
Bookmarks