Actually, I think if the message has not been opened it can be rescinded b the sender and the recipient only sees that the original message was sent but recalled.
You are correct. If the mail has not been downloaded by the recipient, it can be deleted from the server, if it has been downloaded but not read, it can be deleted from the users account. If it has been read, the user will get a second message.
Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.