Comcast - whose customer service ratings tanked during its failed $45 billion deal for Time Warner Cable - has made substantial improvements in customer satisfaction, according to the American Customer Satisfaction Index to be released Wednesday.

The Philadelphia company's 2016 score jumped about 15 percent in the pay-TV category to 62 from 54 a year ago, and about 5 percent in high-speed internet to 59 from 56.

The index is a 100-point scale and based on consumer responses to questions on price, reliability, and service quality. The nation's two top-ranked companies , both with scores of 86, were Chick-fil-A restaurants and the Wegmans food retailer.

Comcast remains among the nation's lowest-rated companies for customer satisfaction, according to the Michigan company that produces the index.

Its internet service ranked sixth from the bottom of about 340 companies or brands. The Xfinity pay-TV service ranked 11th from the bottom.

The 62 score for Comcast's TV service is roughly a return to its 2013 score, which was 63.

The score fell in 2014 and 2015 surveys, said Forrest Morgeson, the research director for the index, said on Tuesday.

Comcast's internet satisfaction rating of 59 for 2016 is higher than last year's 56 but lower than the 62 in 2013.

Still, Comcast posted a "huge gain," and "it will be a test to see if they can maintain their level," Morgeson said.

Comcast's top executives vowed in 2015 to hire 5,000 additional customer call center representatives and technicians to improve the company's customer service.

Charlie Herrin, the cable division's executive vice president of customer experience, said Tuesday that he was happy with the new satisfaction numbers because they were "directionally positive." But he added that "we still have a lot of work to do. We understand that."

"The way I look at, we've got an unwavering commitment to this journey and will take time," Herrin said.

Comcast CEO Brian Roberts and cable division head Neil Smit said improving the customer experience was a top priority at the company, though experts have expressed skepticism that the company will follow through.

Improved reliability of Comcast service's - fewer internet or TV blackouts - has been a factor in the higher satisfaction, Herrin said.

The company also has opened three new call centers.

ASCI L.L.C., a for-profit research company spun out of the University of Michigan and based in Ann Arbor, Mich., produces the index. Its telecom ratings - which include Comcast - were based on 13,000 customer surveys in March and covers pay-TV, high-speed internet, wireless carriers, cellphone manufacturers, and land-line phone service.

Time Warner Cable also had gains in customer satisfaction. Comcast and Time Warner Cable faced a public backlash over their customer service when the two companies proposed to merge in a $45 billion megadeal in 2014. The companies abandoned the deal after federal regulators opposed it in early 2015.

"Consumers are smart and they know they lose out in those kinds of deals," Morgeson said.

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