You can now dispute a credit report item online. It’s the fastest and easiest way to submit a dispute. You can even check on the status of your dispute at a later date.
TransUnion customer service representatives are available to assist you with the dispute process.
If you choose to dispute by mail, TransUnion provides a Request for Investigation form. You can download this form, fill it out and mail it, and you should expect a mailed response from TransUnion within 45 days.