Send Certified U.S. Mail
When you have finished your dispute letters, it's important that you send them Certified Mail. Just ask the postal clerk to add a standard certified receipt to your letter. The cost is around two dollars.
Mailing your letter requires a bureau employee (checker) to physically open your letter, read your dispute, digest the information and investigate your claim. This takes up more time and because the bureau has only 30 days by law to investigate, it is to your advantage.

Don't Forget to Include
The credit bureaus will only accept a dispute if it includes a photo ID and 2 documents verifying your address such as utility bill or a mortgage statement.
Once received, the bureau must investigate your dispute within 30 days. If the credit bureau finds that the information you disputed in inaccurate or unverifiable, it's required to remove it from your credit report. The credit bureau must also notify the furnisher that it's been removed. With your permission, the creit bureau can send your updated report to any employer who has requested your credit reportwithin the last two years, or to any other business who has requested your credit report within the last six months.
The results of the investigation will be mailed to your home. If the issue was not resolved, simply create a 2nd round dispute and re-send.