qgvdial has a network timeout of 45 seconds. If you abort the call, qgvdial has to send another network request to Google voice to cancel the call. Here's my theory of what happens: In the scenario you describe, the first call is pending, then you cancel it, which causes qgvdial to send more network data (which isn't going anywhere because of the terms and conditions page). Because of this, the next call says "Another call is in progress". You'll have to wait for 45 seconds per request for that timeout to expire.