File a written dispute first — why and how (first half). If you discover an incorrect late payment on your credit report, the safest immediate action is to file a written dispute with the consumer reporting agency and gather supporting documentation. Written disputes create a record that triggers a formal investigation under consumer-protection rules in many jurisdictions, and they force the bureau to ask the furnisher (the creditor) to verify the item. Collect bank statements, payment confirmations, or correspondence that show the payment date or proof of clearing, and attach copies (never send originals). A clear, documented dispute is stronger than a phone call because phone conversations are harder to verify later; a written dispute produces a timestamped paper trail you can reference if the error persists. In parallel, contacting the original creditor (in writing) to confirm their records is helpful — but the priority is to get the bureaus investigating because lenders and many automated systems rely on the bureau’s reported file.

Practical follow-up steps and outcomes (second half). After you submit the dispute, monitor the bureau’s response (they typically have limited time to investigate). If the bureau corrects the error, confirm the updated report and keep copies of the corrected documents. If the result is incorrect or the furnisher fails to verify, escalate: send a follow-up letter, request a statement of dispute on your file, and consider contacting a consumer-protection organization for guidance. If the error was caused by a misapplied payment or identity mix-up, maintain the documentation and ask the creditor to provide a letter confirming the account status so you can share that with future lenders. The overall goal is to remove inaccurate derogatory items because correcting them often has an immediate positive effect on score and loan pricing.