But the addressee doesn't know anything about the rejection of this
e-mail and continually calls me in order to know where is his e-mail.
After telling him a lot of time that his e-mail has been refused
because the sender had sent him a virus not by his will, he has
thanked me for the service but begged me to tell him something when
I reject a message. The customer perfectly knows that I will send him
a lot of useless e-mails but he accepts it and, at the end, he pays.
But I really have no idea about how it works.