Problem with a company's investigation into an existing problem: Credit reporting or other personal consumer reports

I have made several good-faith attempts to dispute these inaccurate and unverifiable accounts, yet my concerns have been repeatedly ignored. This continued failure to properly investigate the disputed information is unacceptable. I DEMAND that you conduct a thorough investigation of each disputed account and provide me with a complete description of the procedure used to verify its accuracy, including the documentation relied upon during your investigation. If you are unable to verify the accounts with competent evidence, I DEMAND that they be REMOVED from my credit report IMMEDIATELY. I expect a timely written response confirming the results of your investigation and the actions taken to resolve this matter.