phone company billing

Why is it that the phone company is incapable of billing people correctly? Was there some ancient memo sent out back in the "Bell" days that stated that no baby bell could bill their customer properly? It doesn't matter which phone company you are referring to - every Baby Bell that we've had service with manages to screw up our phone bill - EVEN when I worked for one of them.

Some are worse than others. Some only mess things up when you go to make a change. With others, the only thing you can rely on is your bill unexplainedly changing each month. Calling them seems to be hit or miss. Sometimes you get a customer service person that is knowledgeable and helpful - at other times you get a moron. Why is it that companies that are so large refuse to hire decent help at respectable pay rates? I suspect that many of them are subcontracting their customer service to companies paying minimum wage and no benefits. What else could explain the fact that so many of their customer service people just don't seem to care?