Related Clues:

• Forwards
• Transmits twice
• Mails again
• Responds to "I never got it"
• Transmits again, as an e-mail
• Responds to the MAILER-DAEMON
• Forwards, say
• Makes sure that text went through
• Forwards, as a misdelivered letter
• Emails anew
• Makes up for missing merchandise
• Forwards, perhaps