Is the reporting by the original creditor of their account, by a debt collector on the collection of a debt that was derived from an OC?
Requests for debt validation apply only to debt collectors, not original creditors.
Notification of debt asserted by original creditors is done by way of your account agreement with them, and their subsequent billing statements.
How to proceed thus depends on who the "company" is.
If they are the OC, then you should have records and knowledge of dealings with them.
If you have no knowledge of having had any debt obligation with them, then the identity theft process is most likley your next step.
You simply file a police report stating that you never authorized any account or transactions with them, and thus their assertion of debt could only have arisen as a result of someone else using your identity. Armed with that police report, you can then send a copy to the CRA and immediately get their reporting blocked from your credit report, and send a copy to the creditor and demand all business records in their possessiont related to the alleged debt/account/transactions.
