47 CFR § 76.1619 - Information on subscriber bills.
(a) Effective July 1, 1993, bills must be clear, concise and understandable. Bills must be fully itemized, with itemizations including, but not limited to, basic and premium service charges and equipment charges. Bills will also clearly delineate all activity during the billing period, including optional charges, rebates and credits.
(b) In case of a billing dispute, the cable operator must respond to a written complaint from a subscriber within 30 days. The required response may be delivered by email, if the consumer used email to make the request or complaint directly to the cable operator, or if the consumer specifies email as the preferred delivery method in the request or complaint.
(c) A cable franchise authority may enforce the customer service standards set forth in this section against cable operators. The franchise authority must provide affected cable operators 90 days written notice of its intent to enforce standards.