It will stay on your CR, but annotated with "Paid, settled for less"
The account stays, but updates stop.
Account will be removed no later than 7.5 years from DOFD.
You can grab a copy of free annual credit report and see either DOFD or projected removal date.
We still cannot answer the refund question, because it's unclear what happened to it.
Did you just forgot about it and fees + interest accumulated?
Did someone else make additional charges?
You said it's yours, then you said you got statements and it's not yours, so we're all tripping there.