If you find mistakes on your credit report- such as incorrectly reported amounts on an account, or an account that doesn’t belong to you, you can fill out the dispute form included on a mailed copy of a credit report, or use an online form to dispute the discrepancy online.
The credit reporting agency must then verify the information within 30 days of your filing the dispute (or the mistake must be removed). If they find it to be correct, and you still disagree- you can contact the creditor directly to have it corrected. If they find the information you’ve disputed to be incorrect, they are required to remove the item from your credit report.
Article from destroydebt.com