If collections are appearing in your CR, the very fact of their reporting is considered an "initial communication with the consumer" that invoked their requirement under FDCPA 809(a) to have sent you a formal collection (dunning) notice within 5-days of that credit reporting.
Did they ever send you dunning notice? If they did, unless you live in Texas, you only have 30-days from date of their dunning notice to send a DV letter that invokes any compliance with FDCPA 809(b), and even if the DV is timely, they have no requirement to respond. Your DV letter, if timely, would merely invoke the cease collections provisions of FDCPA 809(b). Since they are not conducting collection activities at this point, I see little to be accomplished.
You can still send a DV request, but it has no compliance teeth if not timely. They will most likely place it in their circular file.
You can, of course, send a PFD request, if you are willing to pay for earlier deletion. If it is outside of SOL, there would be no issue of legal action.