After sending a DV letter to Equable Asset Financial (EAF, Hilco Receivables) and subsequently disputing with the CRAs, EAF changed the Date of First Delinquency to a date four years more current. Is it time to sent the Intent to Sue letter?
I don't know that an "intent to sue" letter is really useful. I've seen samples of one floating around out there, and maybe they did a lot of good back in the early 2000s. These days CAs / CRAs / OCs are wise to the fact that these letters exist, and probably get dozens (or hundreds, or thousands) of them weekly. I think the answer to your question is really a matter of preference. I personally prefer the "speak softly and carry a nuclear warhead" option. If I found myself in your shoes, I think I'd send a CMRR advising them of their "mistake" and requesting that they fix it within 30 days. Then I'd check my credit report 90 days after their receipt of the letter. If it hasn't been fixed, I'd gather paperwork proving that the older date is correct and sue them under the FCRA. Possibly the FDCPA (prohibited actions), though I'd have to do some homework first. It's my belief that you want to demonstrate that you gave the CA / OC / CRA a fair chance and plenty of time to fix the problem. That makes your victory in court that much more likely. But the only time I'd tell them anything about a potential lawsuit is when I had them served with papers.
My "letter of intent to sue" is when they receive my filed petition. I have a debt repair business as a client and he was writing these letters, and I told him to stop because he was wasting his time and postage sending them.