No Response from Debt Validation Letter...This Instead

I sent off my "debt validation" letter back in April. After I sent that, I found a lawyer to represent me for free against the practices of the collection agency concerning methods and tactics used in trying to collect. He sent them a letter telling them not to contact me and they haven't. However, they forwarded on my letter onto Capital One and this is the communication I got in return:

"Thank you for your recent inquiry.

Unfortunately, we are unable to process your request with the information you provided. So we can process your request, please fill out the form at the bottom of this letter. Send it, along with a copy of your previous correspondence, in the enclosed envelope to:

ADDRESS

Please complete all the items on this form, even those you may have previously provided. Once we receive this information, we will be able to proceed with your request.

We apologize for any inconvenience . If you have any questions, please give us a call at 800-955-7070. Our customer service representatives are available 24 hours a day, 7 days a week."

The info they requested was my name, my address on file with them, my current address - if it's different than what's on file am i requesting an address change, my account number, my social security number and my date of birth.

What should I do about this? They already know my address. They sent me the letter to my house address! They have all of this information. It was forwarded from a collection agency, who I KNOW has my information. They used it to harass me before they were told to stop contacting me. Any suggestions or advice?