AT&T is trying to convince the Federal Communications Commission to backtrack from a $100 million fine issued to punish AT&T for its throttling of customers on unlimited data plans.

“The Commission’s findings that consumers and competition were harmed are devoid of factual support and wholly implausible,” AT&T wrote in a response to the FCC, according to The Hill . “Its 'moderate' forfeiture penalty of $100 million is plucked out of thin air, and the injunctive sanctions it proposes are beyond the Commission’s authority.”

AT&T claimed it made all the required disclosures to customers, and also that the statute of limitations on the alleged violations had passed. The company also claimed that the FCC is infringing its First Amendment rights by requiring AT&T to tell customers that it violated an FCC rule.

We've asked AT&T for a copy of its response to the FCC's Notice of Apparent Liability, which set out the proposed fine, but haven't received it yet. The FCC told Ars that such responses are not posted publicly by the FCC but that companies can make them public if they want. UPDATE: AT&T has given us a copy of the document. Here it is.

The FCC last month accused AT&T of violating its transparency rules "by falsely labeling these plans as 'unlimited' and by failing to sufficiently inform customers of the maximum speed they would receive under the Maximum Bit Rate policy."

Besides the $100 million fine, the FCC ordered AT&T to correct misleading and inaccurate statements to consumers, make more specific disclosures about data speeds, notify unlimited data plan customers that it violated the transparency rule, and allow customers to cancel their plans without penalty.

The FCC said it could have fined AT&T much more, up to $16,000 per violation for millions of violations. But it chose $100 million to avoid "an astronomical figure" while making the fine big enough to deter future violations.

AT&T's throttling affects customers on unlimited data plans for the remainder of the month once they pass a certain threshold, 5GB for LTE users or 3GB for customers on slower networks. Although AT&T claims it did nothing wrong, two months ago it changed the policy so that all users on unlimited plans would only be slowed during times of network congestion. Previously, LTE users got drastically reduced speeds for the remainder of the month even if the network wasn't congested.

"It is absurd to suggest that AT&T intended to or actually did mislead the relevant Unlimited Data Plan customers. Those customers were repeatedly advised of AT&T’s congestion management practices, and, for nearly four years, they chose to keep their service," AT&T argued, according to Multichannel News.

"AT&T said the FCC does not have the authority to require it to allow customers to evade early termination fees or stop using the term 'unlimited' or to bear the 'scarlet letter' of having to inform its customers that it violated the transparency rule, which it called a violation of the First Amendment," Multichannel News wrote.

AT&T is also being sued by the Federal Trade Commission, which is seeking a court judgment that would bring millions of dollars of refunds to consumers.

Despite fighting the FCC over the throttling fine, AT&T got some help from the commission last week when it approved the company's purchase of DirecTV.