If additional information is requested, send your letter by certified mail, return receipt requested, so you can document what the CRA received.
The FCRA mandates that all CRAs re-investigate the items in question – usually within 30 days – unless they consider your dispute frivolous. They also must forward all relevant data you provide about the dispute to the credit card company. After the credit card company receives notice of a dispute from the CRA, it must investigate, review all relevant information and report the results to the CRA.
If the disputed information is found to be inaccurate, the credit card company must notify all nationwide CRAs so they can correct this information in your file. Disputed information that cannot be verified must be deleted from your file.