Could it have been a home depot or best buy card?
Shhhhhhhhhhh, be very, very quiet. I have one CBNA from 1998- closed 2005. Last reported 2013. It's a gift!
When I started paying attention to my credit I noticed an open Comenity acct I totally forgot about, opened it in 2001. Thought it was closed by lender long ago as I know there had been several lates. But by the time I started the rebuild process those had obviously aged off. It was a measly $100 limit (reduced from what it had been), last reported 2010 but still open and reporting. But I had high UTL overall and left it alone as it was helping my age and minimally my UTL. After I got my scores up and needed a bit more UTL drop to get to the next threshold I called about it and asked that they re-issue a card because I lost it many years ago. Unfortunately, they did a HP but increased the CL to $1000 and re-issued card. For me that was great as I was working to decrease UTL by any means necessary and already received all the CLI I could.
However, sounds like you're not sure it's your acct? That I would question.
Mine continued to be reported with a last update of 4/2010. I think as long as it's still open the CB's won't delete. I had the card re-issued in 2018 to protect me just in case in order to keep the age. Used the card maybe twice to re-establish reporting.
Or you can have it closed and should still be included in age up to 10yrs after close date. That will cause it to report as closed which may re-establish additional reporting for a while.