actually my favourite one is a conference chairperson complaining because he couldn't hear the participants in the call (he had used the "mute all participants" function) and refusing to pay for another conference because the entire conference was filled with orchestral/instrumental music (one of his participants had put the conference on hold) and apparently at the time he did not call for an operator to assist him because that's the kind of thing we regularly work out for conferences if we know it's going on