My first thought was "wow, those assholes."
But my second thought was... how did they make their PBX do that? Is this actually a feature that PBX vendors ship?
Wouldn't be surprised if they have their own internal PBX system with a SIP trunk
I mean, any system has the ability to play a message before putting the call into a queue. Make the message fifteen minutes of muzak…
Many call centers have these privacy messages that play before you're actually put on hold. Just use the same feature with a 15min of waiting music.