Discovery Bank is useless to say the least

I paid up my discovery credit card about 3 years ago and hasn't used it since. About a year ago, I started getting notifications on my e-mail that I had to pay up R90 every month. I paid it, but it didn't stop. I got no statements to say what this was for. On the 12th of January 2024 I called the call centre, requesting that my credit card account must be closed. Credit card ***, The lady said that the card would be closed within 10 days, and I would get a notification e-mail. I got no e-mail. Yesterday I got an e-mail notifying me that I needed to pay R90 before the 29th of January. I tried the call centre, to no avail. No one answered. Now I am logging a complaint, because according to my call, and knowledge this account is supposed to be closed. Discovery Bank, first of all, why must I pay for something I am not using, and why is it so difficult to get my credit card closed?