The American Customer Satisfaction Index has pegged Time Warner Cable Inc. as the nation’s most unloved company.

Based on phone and online surveys, it rated Time Warner Cable’s Internet service as 236th out of 236 companies in customer satisfaction — a list that included Coke, Campbell Soup, Nissan, Allstate and Verizon Communications. Time Warner Cable’s TV service rated 25th.

Comcast Corp.’s Xfinity Internet service placed at 234 out of 236 and its TV service landed at 232 in the list released in May.

Would merging these two cable giants in a megadeal benefit consumers? Comcast says that it will, and that the perceptions of its poor customer service are outdated.

Certainly, the cellar-dwelling ratings of the two companies will stoke the political and regulatory debate in Washington over the proposed merger that has faced fierce opposition.

“This doesn’t pass the straight-face test,” said U.S. Rep. Rochelle M. “Chellie” Pingree, a Maine Democrat who has posted an online petition opposing Comcast’s $45.2 billion acquisition of Time Warner Cable with 161,000 signatures. “Nobody believes that by combining these two companies they will be twice as good.

“People think they will be twice as bad.”

A Time Warner Cable subscriber at her home in southern Maine and a Comcast subscriber in Washington, Pingree says that if people are angry with their TV and Internet service providers now, they have no idea what sort of problems they may face if the two companies merge.

David VanAmburg, managing director of ACSI, the private company that produces the American Customer Satisfaction Index, said he doesn’t see a boost to customer satisfaction through a Comcast-Time Warner Cable combination because they both have such low ratings.

“They are among the lowest scores of any company of any industry we measure,” Van­Amburg said.

The index’s top-rated company was Mercedes-Benz, followed by Amazon, H.J. Heinz, Lexus and Apple.