T-Mobile US CEO John Legere apologised to Electronic Frontier Foundation (EFF) after launching a foul-mouthed tirade against the industry group which criticised its video streaming Binge On service.

In a show of defiance against a report released by the consumer rights group at the start of the year arguing Binge On went against net neutrality, Legere said certain groups were “confusing consumers questioning the choices that we fight so hard to give our customers”.

Addressing EFF directly, Legere asked: “Who the f**k are you, EFF? Who pays you? And why are you causing so much trouble?”

The comments led to a deluge of EFF supporters taking to social media to inform Legere exactly what the industry group represents.

In an open letter, the outspoken CEO now appears to have backtracked, amid pressure, while maintaining a staunch defence of the Binge on service.

“By now you know that I am a vocal, animated and sometimes foul mouthed CEO. I don’t filter myself and you know that no one at T-Mobile filters me either. That means I will sometimes incite a bit of a social media riot, but I’m not going to apologise for that,” he said.

“I will however apologise for offending EFF and its supporters. Just because we don’t completely agree on all aspects of Binge On, doesn’t mean I don’t see how they fight for consumers.”

EFF hit a nerve with Legere after claiming that Binge On, which allows T-Mobile consumers to stream video at lower quality from its partners without hitting data allowances, was actually bringing down the quality of all video across its network, igniting questions over net neutrality principles.

Google-backed YouTube, which is not a Binge On partner, has made similar claims that its video quality has been impacted on the T-Mobile network, as a result of Binge On.

Binge On optimises video quality at a bitrate quality of 480p, which the operator says is of sufficient quality to run on a small screen.

Legere maintained the benefits of Binge On for consumers in his latest comments, adding that it is a free benefit for all its customers, helping them to stretch their data bucket by optimising all video for mobile devices.

He said the company uses technology to detect all video, determine its source, and identify if it should be free and then adjust the quality.

He also said the service is a “very pro net neutrality capability” as consumers have the choice to turn it off whenever they want.

The company announced 14 additional video services for Binge On last week, taking the total number of partners to 38 upon the announcement.

Start-up video service Slidefuse, maker of 4Stream TV, however withdrew from Binge On following Legere’s comments about EFF.