The latest in a string of customer service horror stories for Comcast could cost the cable giant a lot more than one unhappy subscriber.

The company’s proposed $45 billion merger with Time Warner Cable, which is facing increased scrutiny from federal regulators, may hang in the balance.

“The customer service nightmares of the past 12 months certainly aren’t going to help,” said Craig Moffett, a senior analyst at MoffettNathanson. “It’s unclear how much politics matter in these things, but they have to matter at least a little bit.”

Mary Bauer, who lives in a ­Chicago suburb and received an invoice that referred to her as “Super Bitch” after repeatedly complaining about her service, has been offered two years of free cable. And the rogue customer service employee who bestowed upon Bauer the unflattering appellation has been identified and fired, Comcast said.

While Comcast’s situation with Bauer is ostensibly resolved, its merger with Time Warner Cable is stalled, and odds of its approval are decreasing, according to Moffett and other analysts.

Comcast agreed to acquire Time Warner Cable a year ago in a stock transaction that would make the nation’s largest video and high-speed Internet provider even larger.

The deal, which must be approved by the Justice Department and the Federal Communications Commission, has stalled in recent months because of regulatory changes and, perhaps, mounting concerns over the size of the resulting cable and broadband behemoth.

The combined company would control 30 percent of the cable market and about a third of all broadband connections. Comcast has agreed to divest of 3 million cable subscribers as part of the deal to keep its market share at the 30 percent threshold, formerly a statutory limit imposed by the FCC. While no longer mandated, the divestiture is seen as a goodwill gesture by Comcast to help push the merger through, Moffett said.

While there is no limit for high-speed Internet market share, it could prove even more problematic for Comcast in the current regulatory and political environment. The FCC voted last month to redefine broadband Internet standards, raising the minimum speeds and boosting the combined company’s share of the high-speed market to about 55 percent, Moffett said.

“That increases Comcast’s apparent market share, making it easier for the Justice Department to block the transaction,” Moffett said. “But it is also emblematic of a relatively hostile environment in Washington for cable operators right now.”

Hostility on social media

Public hostility toward Comcast and the proposed merger is becoming more palpable on social media as more customer service horror stories come to light.

In July, Ryan Block of San Francisco recorded eight minutes of a now-viral phone call during which a Comcast “retention specialist” all but refused to cancel his service.

Bauer, 63, said she had 39 service calls with Comcast last year before resolving an intermittent cable problem. Then there were months of billing issues, including a credit that never materialized, an unexpected price increase and four months of no invoices at all. The culmination of more than a year of service calls, phone calls and complaints came in the insulting invoice, which arrived in her mailbox last week.

“We’ve identified the customer service agent who was responsible for the name change, and that individual is no longer working on behalf of Comcast,” Comcast spokesman Jack Segal said in a statement. “We’ve also put in place additional technical safeguards that will prevent this from happening in the future.”

That was the same promise made by Comcast 10 years ago, after a remarkably similar incident. In 2005, the Chicago Tribune reported that Chicago-area resident LaChania Govan’s name was changed to “Bitch Dog” on her Comcast bill after she complained about poor cable service.

‘Will never happen again’

At the time, a Comcast spokesman apologized and said the company was “putting things in place so that it will never happen again.”

Comcast has taken steps to improve customer service.

Last month, the company elevated Wendy Liu to the newly created position of vice president of customer experience for the Chicago market, with other regions expected to follow. Liu is tasked with making sure customers have a “great experience,” an ambitious goal that may have become a higher priority in light of growing backlash and the pending merger.

“We’re looking at every single process and every single interaction to determine ways to make our service even better,” Segal said Wednesday.