The contentious proposed Comcast takeover of Time Warner Cable has met with another detractor on Friday. Unsurprisingly, Charter Communications, the company that was trying to bid for Time Warner Cable before Comcast swept in, urged TWC investors not to endorse the merger with Comcast.

When the news originally broke that Comcast was to announce a takeover deal with Time Warner Cable, it was hard to believe -- particularly because all of the news about Time Warner Cable before that focused on Charter Communications' aggressive bids to buy the company.

Charter, the fourth-largest cable company in the U.S., was trying to buy TWC (the number two largest cable company) for $37 billion in cash and stock, which figured to about $132 per share -- a bid that TWC rejected as too low. The Comcast deal seemed to come out of the blue. The Comcast deal, for the equivalent of about $159 per share, seemed to come out of the blue.

That deal, which has fallen to about $142.50 per share, according to Bloomberg Businessweek, has left Charter sour. It's formally urging in a filing that the shareholders of Time Warner Cable, Inc. to reject the buyout agreement.

It specifically said that the Comcast deal would be subject to too high a degree of regulatory risk, saying that it is "difficult to imagine a transaction that could concentrate the industry more," as Comcast would hold about 40 percent of the U.S. cable market, before it divests in millions of TWC subscribers to reach the 30 percent maximum set by regulations.

Charter, a cable company like the rest, of course did not emphasize the Net Neutrality and anti-competition concerns the deal has brought up from a consumer/netizen standpoint, but rather claimed that regulatory scrutiny would drag the deal out to a degree that it would hurt TWC's business relationships -- and thus the bottom line. Charter said the Comcast/TWC deal could take until the third quarter of 2015 to be worked out, and could then still fail. The company also alleged that Time Warner Cable's board never engaged with Charter's offers on a potential deal in a meaningful way, and noted that even after announcing the Comcast merger, the value of Comcast's offer has declined due to its dwindling stock price, which has lost about 13 percent since the buyout was announced.

A representative from TWC responded to Charter's filing saying, "We are fully committed to our merger with Comcast, which we believe is in the best interests of shareholders," according to MarketWatch. Charter did not respond to MarketWatch's request for comment.

Besides Charter's self-interested criticisms, the Comcast/TWC deal has been seen as a potential problem for Net Neutrality and broadband competition. With a single cable company owning the only cable broadband option for about a third of the country, Comcast could be a powerful giant with a lot of sway -- and an entertainment/news empire in NBCUniversal -- once its vow to follow the Federal Communications Commission's 2010 net neutrality-friendly Open Internet standards expires in 2018.