Shortcuts to solve replacement card issues

New replacement card due to old one expiring. When online, the new card card does not work. Phoned Discovery, the lady mentioned that the old card was not properly deleted on the system when I deleted from the App. The new card has the exact same card number as the old one. Online, this card number find the old card details, which is cancelled, so it does not work. The lady on the call said we must add a visual card, that will fix it with no help offered to fix the actual card. Even when I insisted, the said we must just continue with the virtual card.