I think you'll find that most reputable companies have a policy of allowing customer service reps to dump any caller who is irate or abusive... I know this to be a fact at Parceline, City Link and Tuffnells Parcels Express as I have worked for all of them and as part of training you have to do a spell in Customer Services. I would suggest that it is common to the whole industry based on this.

Also, the calls are recorded which allows a customer service rep the confidence to dump an abusive call knowing it can be verified later.

Fotune 500 or not, all companies these days take abuse of their staff as seriously as customer service.