Once the OC creditor feels they won’t get there money back typically they just count it as a loss and report it as a charge off
When OC sell the debt to CA they will then 0 out the amount owed, The collection company that bought it will then report there line as a collection, just because you had the collection account removed doesn’t mean the OC will remove there’s, theres several post about goodwill letters and that would be your best bet, just make the letters as personal as you can when writing them.