There need be no prior reporting by the OC in order for a collection to appear.
I would begin by sending a DV to the debt collector. That imposes a cease collection bar on them until such time as they provide verification of the debt.
The DV statute does not require them to provide the name of the OC unless specifically requested in the DV, so be sure to include that request.
However, that wont assure prompt resolution, as they have no time period in which to provide verification. You could sit in limbo unless and until they provide verification.
In the meantime, if they did not send dunning notice within 5 days of their reporting, they are in violation of FDCPA 809(a). I would suggest sending a formal complaint to the FTC, with a cc: to the debt collector, making their violation of written record.
Additionally, if you can state in writing that you never authorized any account with that OC, you have the ability to require both blockage of any reporting made to the CRAs as well as compelling the OC to provide relevant documentation. That is done by putting your statement into the form of a sworn police report, which if sent to the CRA requires blocking of the collection from your CR, and if sent to the OC, requires them to provide all business records related to the alleged account.
If you can honestly make such a sworn statement, I would file a police report, and pursue the identity theft provisions of the FCRA.