For duplicate account reportiing to your credit file, the issue is one or innacurate credit reporting under the FCRA,
DV letters are under the FDCPA, for the primary purpose of ceasing collection activity until a full DV is received. The FDCPA does not deal with credit reporting, it deals with debt collection practices.
So, no, I would not follow the DV process with the CA to correct duplicate reporting.
I would file a dispute with the CRA under FCRA 611(a) and FCRA 623(a)(2) asserting failure to correct and update information with the CRA. That also requires a 30-day response period that is not present in the FDCPA.
