A collection agency mailed me a collection letter for something I didn't recognize. It said to respond within 30 days or they're gonna assume the debt is valid. I responded immediately disputing the validity of that debt and asking for proof. I never heard back from them. That was 40 days ago. Today, the original creditor (centerpoint) reported that account on my Experian credit report. How should I proceed? Should I dispute with Experian and just wait? Or should I dispute with both Experian and the original creditor at the same time? When I dispute with Experian, should I just dispute it's not mine or should I also include proof and I requested validation from the collection agency and that they failed to respond?