Discovery Bank not reacting to call centre request

Some weeks ago, I called Discovery Bank via their call centre to cancel a secondary card on my card account that was no longer being used. I had attempted to do this on the banking app, but it kept showing as "pending." The card was in my wife's name and prior to my call I was getting SMS and email notifications in my wife's name to update her details which have been unchanged for many years, we are both pensioners. I was assured by the call centre contact that the card was now cancelled and that SMS and email requests would stop. It has not stopped and I am receiving requests every few days to update my wife's details. Today eight emails and eight SMS's! I am not prepared to go through the whole call centre process again - how can I stop this ridiculous situation?