Thing is my original creditor knows my address, which is where the DCA got it from. So I feel they would be fairly confident they know where I am so not sure why they would need to 'phish' in that sense?

Hi all updating an old thread. I lost the password/email to my previous account so created a new one. So after months of my letters being ignored I finally gave up. The debt has been bounced around a few UK DCAs but none of them were following up in the payment of the debt. Situation has changed now because for the first time a US DCA (in the same state where I live) has now gotten involved. The DCA in question is 'Caine & Weiner' and unfortunately they're demanding an amount I'm not even close to be in a position to pay. The letter they've sent mentions that they have a 30 day window to request 'validation' of the debt, which I think it's cautious and prudent to do as I've stop receiving any communication from the original creditor about the status of my account. Does anyone have a template or advice what I should put in my written response back to them (The letter is dated December 3rd, so I don't have a large amount of time to respond to them). Is there specific evidence I should be asking for now for proof in case this goes to court later?