When someone gets into your cell phone, or computer, and steals the names and e-mail addresses from your contact list, then starts sending stuff using those names and addresses as having originated messages - what's that whole process called. I suspect it is more than a "hack," but have been unable to find another term. I, personally, have received odd messages from contacts, and an inquiry results in a "thank you" for alerting them to the fact that somebody else is sending messages using their address.