Unable to renew expiring Discovery card

I have a Discovery Visa card, and my wife has a secondary card linked to it. She received several notices to remind her that her card was expiring at the end of this month, so I app**** for a replacement, which was delivered. I was not able to authenticate the new card by following the instructions, because the new card was not shown next to her name - only the old card was there. I phoned the helpline and was told I first had to download the banking app. I did this and the only way forward seemed to be for me to apply for a new card for myself, which I did. But, still no indication of how to get a card for my wife. On phoning again I was told that, once my new card had been issued, I could apply for a secondary card for my wife. This is all very obscure, and I cannot understood why I waited home to receive a useless, unusable card for my wife. I wish it was possible to write to Discovery, but the helpline seems to be the only access.