He knows because he worked as a phone company service representative.
"Most of the calls we received people had been waiting a while. People were mad. They were angry," says Contreras, a former SBC Pacific Bell employee.
Contreras spent five months in the San Diego offices of SBC Pacific Bell at a time when the company was aggressively pushing a costly new service: DSL, high speed Internet access.
According to Contreras, "It was sell DSL, sell DSL to everybody."
"SBC was gripped with a fever of selling. There were selling DSL as hard as they could, even though they knew they were having real difficulties providing that service," says Michael Shames with the Utility Consumers' Action Network.
Clothing storeowner Heidi Newell ordered the DSL service. "I needed the service so I could run my business", she says. But when it didn't work she could not get the charges taken off her phone bill.
Then, SBC threatened to turn off her telephone service, and they did –- for failing to pay for the DSL service that she never received.
SBC Pacific Bell refused to be interviewed for this report. But in a statement, said the billing problems grew from "pioneering…new technology" and have since been solved.
But SBC Pacific Bell has been fined a record $27 million for the DSL bill errors. The company admits as many as 70,000 customers may have had mistakes on their phone bills.
Gary Cohen of the California Public Utilities Commission says competition and tough economics are pushing phone companies everywhere to the edge. "I think it definitely is a national problem," he says.
"The hunger for more market share by these companies has caused them to do things that are just absolutely, you know, against the law and really harmful to consumers," explains Cohen.
"They have on record 42 calls that I've made in the last year. The average call minimum I would say would be an hour. It's the closest I've ever come to a nervous breakdown, I swear," says Newell.
Consumers can do little more than keep a close eye on their bill and brace themselves, if, like Heidi Newell, they have to fight back.