Unless you have old reports that show the OC you might have to take the DOFD/DOLA reported by the CA.........look on your TU and EX report for the drop date *will remain on CR until month/year*. Or call the CRA and ask.
I would never trust the CA to give correct info. Can you guess when the dates should be?
Usually if the OC stopped reporting it is past CRTP that is IF they ever reported.