When Time Warner Cable merged with Charter Communications earlier this year and the new public-facing operation rebranded, changing its name to Spectrum, it was likely for good reason. For many Americans, each name had come to be associated with poor customer service.

The long erosion of reputation has the power to destroy businesses. Today, in the internet age, news of a single scandal can spread quickly and seriously cripple a previously respected brand. 24/7 Wall St. reviewed a range of information, including customer survey results from the American Customer Satisfaction Index, employee reviews on Glassdoor, as well as our own annual customer satisfaction survey. We identified 12 companies hated by customers, employees, and the general public.

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A single bad experience can forever ruin a company’s image in the mind of a customer. While these are bound to happen at any organization, many of the companies on this list have developed a reputation for consistent poor performance. Most of the companies on this list score worse than the average in their industries in the ACSI. This fact is all the more serious given that many of these companies are in industries with generally poor reputations for customer service, including cable and internet service providers, airlines, and subscription television services.

In 24/7 Wall St.’s annual customer satisfaction survey, the majority of these companies had among the highest share of respondents reporting generally negative customer experiences. In the case of Comcast and Sprint, more than half of respondents had a negative customer experience, the only two existing brands out of the more than 100 we surveyed for which this was the case.

At several of the companies on this list, employee satisfaction is also extremely poor. 24/7 Wall St. spoke to Scott Dobroski, community expert at Glassdoor, a site that allows employees to rate their employment experience. Dobroski explained that it is not surprising to see unhappy employees and unsatisfied customers at the same businesses. “The risk when you have employees that are generally dissatisfied is that they are not willing to bring their best selves to work, to produce, to be engaged, and to fulfill responsibilities," Dobroski said. "When employees are generally satisfied in their jobs -- we know that there's a direct tie to the customer experience.” Dish Network and Sears each have close to the worst employee satisfaction scores earned by large corporations on Glassdoor.

In the case of Sears, Dobroski suggested that poor employee satisfaction might also be tied to dread of the company failing, as Sears has been in dire financial straits for years. The company has averaged $1.65 billion in net losses over the last five fiscal years and closed hundreds of locations.

Several of the companies to make the list this year, rather than suffering from long-term damage to reputations, have only recently earned the ire of the general public. Pharmaceutical company Mylan has been exposed to severe public outcry after it was revealed the company hiked prices of life-saving allergy treatment EpiPen by more than 500%. Wells Fargo lost the public's trust after news broke the bank had created millions of fake accounts to inflate sales numbers.

To identify the most hated companies in America, 24/7 Wall St. reviewed a variety of metrics on customer service, employee satisfaction, and financial performance. We considered consumer surveys from a number of sources, including the American Customer Satisfaction Index (ACSI) and a Zogby Analytics poll created in partnership with 24/7 Wall St. We also reviewed employee satisfaction based on worker opinion scores on Glassdoor — this is not a Glassdoor commissioned report. Finally, we reviewed management decisions and company policies that hurt a company’s public perception.

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These are America's most hated companies.

1. Comcast (CMCSA)

The internet service provider and subscription television service industries are not known for superior customer service. In fact, the two industries have the worst average scores in the American Customer Satisfaction Index. Still, Comcast has a significantly worse customer satisfaction score than either industry average.

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