Once you get the green cards back you must immediately dispute those same ca accounts with all 3 credit reporting agencys.
Its called a 1-2 punch.
Basically the CA cannot validate the debt with the CRA's after you have DV'd them, until they provide you with the proof. Since they just got the DV letters you should dispute those same accounts and until they provide you with proof they cannot verify with the CRAs or that is a violation.
I used this to remove two Palisades accounts that were on my credit report. They never once sent me any letter and just showed up on my credit reports. I DV'd them, then when I got the delivery confirmation I disputed with all 3 CRAs and they fell right off.