I'm disputing inaccurate information posted by a CA on all 3 bureaus. If I receive notice from the CRAs that the debt has been investigated and verified...which would not be true....what is my next step?
You need to take up the dispute with the CA. You can't do anything to the CRA's for reporting what the CA said to them. If you still disagree with the CA then you can speak to a lawyer about a possible lawsuit or arbitration.
What specifically did you dispute? A dispute only investigates and either verifies or corrects the accuracy of the information subject to the dispute. The post states that "the debt has been investigated and verified."
Did your dispute assert the debt itself was not legit, or did you dispute some other information reported under the collection?
If you disagree with the outcome of a dispute, there is no formal appeal process.
You can request reconsideration if they clearly failed to consider some aspect of your dispute.
However, the next legal step is to bring civil action asserting a lack of reasonable investigation of your dispute, and get review by a higher power... the courts.