"This account is currently out of funds. To complete this call, please add credit to the account or place a collect call."
So the buzzer runs out as we are trying to remember how to make a collect call (to voicemail no less).
Afterwards we asked the staffer how we were supposed to fetch the voicemail, and she said "wait, there was a voicemail on the phone?" Turns out there was also an already-read text message on the phone that we were supposed to look at, but we were successfully red-herringed by some random person leaving a message at the wrong number.