I think the main point that people are missing is this:
A good customer services representative should seldom be abused. They should nearly always approach the manner in a positive fashion and always, at all times show that they are attempting to correct a problem that they are entirely to blame for.
It stands to reason that tempers are going to fray when it comes to such issues. However if the response to customers from Customers Services Reps when they pick up the phone is "firstly can I apologise for any fault that has occured and inform you that during the course of this phone call we will attempt to identify and rectify the root cause of said problem" rather than "Hi, I understand you have a problem" then you are always going to be onto a winner.