Junkmail Robots were robots used to send messages.
Kingpin once used a Junkmail Robot to contact the Seventh Doctor for help. (AUDIO: The Psychic Circus)
Behind the scenes
The Junkmail Robot strongly resembles a Kerb!am Man from Kerblam!, another Delivery Bot. Like the Kerbl!am Man, the Junkmail Robot was able to breach the TARDIS.