If you have filed a billing error dispute, the bank cannot make (or threaten to make) an adverse report about your credit standing, or report that a disputed amount—or related finance or other charges—is delinquent to any person, including a credit reporting agency while the investigation is ongoing.
However, the creditor can make an adverse report if you have failed to pay any portion of the undisputed amount due.
If you want to file a complaint with the Office of the Comptroller of the Currency (OCC) Customer Assistance Group, visit the File a Complaint page.