15 U.S. Code § 1666 - Correction of billing errors (b)(3) under the Fair Credit Billing Act (FCBA):
(b) Billing error
For the purpose of this section, a "billing error" consists of any of the following:
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(3) A reflection on a statement of goods or services not accepted by the obligor or his designee or not delivered to the obligor or his designee in accordance with the agreement made at the time of a transaction.