That letter is not going to get you any more than the first one did. They do not have an obligation to provide most of the information it requests. Send them a second letter, simple, just say that you have received their letter but it does not prove to you that the debt is yours. Ask them to send proof that the account was opened by you, and an accounting of how they arrived at the balance. Again, CMRR. You are compiling a paper trail here.
UPDATE: I appreciate the opinions that were posted in this thread. Today, I had a look at my 3 credit reports and the NCS collection account status has changed to CLOSED. This status was UNPAID as of the last time. Now reg. my score: I had a score of > 650, before this collection activity was posted. And when it did, the score plummeted to <550. Now after all the letter writing to NCS, and the account being closed, the score didnt change to what it was earlier. I propose to write letters to all 3 beaureus, and ask them to DELETE the collection activity line item. Will that help? Though it is CLOSED, It goes to say that I owed NCS some money and paid it off. That is not the case here. I never owed NCS any money, but they reported; I sent a letter to NCS, and they did investigation, found I never owed any money and apparently "closed" their claim on my credit file. Please advise.