What's the point?

I recently decided to upgrade my credit card from the FNB Gold Credit Card to the FNB Premium Credit Card. The transition to this was smooth. However, in the month of upgrading my credit card I noticed that the Gold Credit card account is still active on my FNB app. Later on, I noticed that my credit check report on ClearScore showed that I now look like I have two credit cards, instead of the one and it has therefore combined the credit limit that I have. Resulting in what looks like: my credit limit x2. Because of this, my credit rating has dropped. I phoned FNB customer services, only to be told that will be rectified in 90 days! This is completely unacceptable and detrimental to my credit score. What is the point of upgrading if it ruins your credit score.