While this has been discussed in many threads prior, it bears repeating here. If someone opens a Capital One account with less than good credit scores, say 650 or less, that account will forever be viewed as a starter account and will never grow much at all. It doesn't matter if a year and a half later you've got 800+ scores across the board and you've got multiple 5-figure limit, newer cards that dwarf the limit of your older Capital One card. You may get a $1000 CLI or $500 CLI or two from Capital One and sneak your card up to a $3000 or $4000 limit, but that's where it will plateau and stay forever, until the day you close it.
Trying to go up the ladder in these situations and get the EO involved in hopes of getting a different result will be met with no success. The only solution here is to close the original card (or keep it open if you want) that was started on less than good terms and open a new card today which will be opened with good-excellent terms and Capital One will hand you a SL that's probably 2X-5X the limit of the card they refuse to CLI you on. It's just the way CO operates.
