How do I upgrade OneCard to Unsecured?

I have SMB OneCard for 2 years now. And there is no option to upgrade the card to unsecured or even increase the FD limit. I now have 2 unsecured credit cards with way higher limits than the OneCard. But the customer support of OneCard always asks me to wait. No firm response. I can't even close that card as it's the oldest I have.

If anyone here has received any solution, please help me understand. Thanks!