• by Wendy Davis  @wendyndavis, July 28, 2015

The Federal Communications Commission's attempt to sanction AT&T for its mobile throttling policies is "unjustifiable and unsustainable," the telecom says in a recent regulatory filing.

The company adds that the "only responsible course" is for the FCC "to recognize its error," end its investigation and withdraw its complaint against the telecom.

AT&T's filing comes in response to a "notice of apparent liability," unveiled by the FCC in June, which alleges that AT&T violated a net neutrality rule by failing to adequately disclose how it throttles some smartphone users. That rule, which dates to 2010, requires broadband providers to "transparently" state their broadband practices.

The FCC proposes that AT&T pay a $100 million fine and inform customers that its throttling program didn't meet the FCC's transparency standards. The FCC also wants AT&T to offer consumers remedies, including allowing them to opt out of contracts without a penalty.

The dispute stems from AT&T's 2011 decision to drastically slow the mobile broadband speeds of the customers who pay for “unlimited” data, after those customers exceed a monthly cap.

AT&T implemented that throttling policy -- referred to as the MBR ("maximum bit rate") policy -- soon after introducing “tiered” billing plans, which require customers to pay for a monthly allotment of data. The wireless provider still allows longtime users who previously had unlimited plans to avoid pay-per-byte billing, but slows some of them down after they hit a cap of either 3GB or 5 GB a month, depending on their phones' features.

In some cases, AT&T allegedly cut consumers' speeds down to 512 Kbps -- which is too slow for features like video streaming, mapping applications and video chat apps. (Earlier this year, the company stopped automatically throttling unlimited customers after they exceed the cap. Now, the company throttles those users only when the network is congested.)

AT&T argues in its latest filing that it provided customers "with extensive, numerous, and complete disclosures regarding the MBR policy and how it might impact their usage."

The company elaborates that it describes the policy on its site and also notifies subscribers when it sends monthly bills. AT&T adds it "emailed its heaviest users and texted all potentially affected customers with information about the operation and effect of the program."

AT&T also argues that the FCC's complaint is barred by a one-year statute of limitations. The telecom says that the FCC's "one-year window" expired in 2012, one year after the company started throttling consumers.

In addition, AT&T says that the proposed sanctions -- including the $100 million fine -- are "arbitrary and excessive."

"To the extent that AT&T’s website could be found not to satisfy the requirements of the Transparency Rule, that would be a single violation of the Rule supporting, at most, a $16,000 forfeiture penalty," AT&T argues.

The FCC isn't the only one challenging AT&T's throttling practices. The telecom also faces a lawsuit by Federal Trade Commission, which alleged in a complaint filed last year that the company deceived people by offering them “unlimited” data, but slowing them down when they consumed more than a fixed amount.

Also, an Alabama resident has filed a potential class-action lawsuit alleging that the telecom violated its agreement with unlimited data customers.