You can try upgrading through customer service chat or phone call. If they can't upgrade you just apply for a new Cap 1 card that you want. Your SL should be much better than your previous card.
try that link, I upgraded my platinum to a quicksilver no AF.
I got my card a few days after discharge and upgraded it 3 months later.
I have upgraded several cards, just keep using the card and paying it and checking back.
Also, sometimes you can get AF removed without upgrading the card itself.