Then you can say "Hi Bob from Zipcar, Fred from XM radio, and Kate from FitGym, I'd like to cancel all your services."
If one puts you on hold, you talk over the hold music to speak to the other ones on the call.
Gets the job done much quicker typically.
Same for "press 1 for ..." type menus.
Sometimes the automated system says embarrassing things like "The balance of your account is..."