39 U.S. Code § 3662 - Rate and service complaints
(a) In General.— Any interested person (including an officer of the Postal Regulatory Commission representing the interests of the general public) who believes the Postal Service is not operating in conformance with the requirements of the provisions of sections 101 (d), 401 (2), 403 (c), 404a, or 601, or this chapter (or regulations promulgated under any of those provisions) may lodge a complaint with the Postal Regulatory Commission in such form and manner as the Commission may prescribe.
(b) Prompt Response Required.—
(1) In general.— The Postal Regulatory Commission shall, within 90 days after receiving a complaint under subsection (a)—
(i) upon a finding that such complaint raises material issues of fact or law, begin proceedings on such complaint; or
(2) Treatment of complaints not timely acted on.— For purposes of section 3663, any complaint under subsection (a) on which the Commission fails to act in the time and manner required by paragraph (1) shall be treated in the same way as if it had been dismissed pursuant to an order issued by the Commission on the last day allowable for the issuance of such order under paragraph (1).
(c) Action Required if Complaint Found To Be Justified.— If the Postal Regulatory Commission finds the complaint to be justified, it shall order that the Postal Service take such action as the Commission considers appropriate in order to achieve compliance with the applicable requirements and to remedy the effects of any noncompliance (such as ordering unlawful rates to be adjusted to lawful levels, ordering the cancellation of market tests, ordering the Postal Service to discontinue providing loss-making products, or requiring the Postal Service to make up for revenue shortfalls in competitive products).
(d) Authority To Order Fines in Cases of Deliberate Noncompliance.— In addition, in cases of deliberate noncompliance by the Postal Service with the requirements of this title, the Postal Regulatory Commission may order, based on the nature, circumstances, extent, and seriousness of the noncompliance, a fine (in the amount specified by the Commission in its order) for each incidence of noncompliance. Fines resulting from the provision of competitive products shall be paid from the Competitive Products Fund established in section 2011. All receipts from fines imposed under this subsection shall be deposited in the general fund of the Treasury of the United States.